Communication control device, communication control method and information processing apparatus

ABSTRACT

A communication control device that acquires first interference information indicating a first interference from communication involving a communication node that is not controlled by the communication control device and second interference information indicating a second interference from communication involving another communication node that is controlled by the communication control device. The communication control device classifies the communication nodes into groups related to a decision of a radio resource that is available for use by a communication node based on the first interference information and the second interference information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/014,649, filed Jun. 21, 2018, which is a continuation of U.S.application Ser. No. 14/769,904, filed Aug. 24, 2015 (now U.S. Pat. No.10,044,450), which is a U.S. National Stage application of InternationalApplication No. PCT/JP2014/056343, filed Mar. 11, 2014, which claimspriority to Japanese Application No. 2013-098247, filed May 8, 2013, theentire contents of each are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a communication control device, acommunication control method, and an information processing apparatus.

BACKGROUND ART

In recent years, the wireless communication environment is confronting aproblem of depletion of frequency resources, due to rapid increase ofdata traffic. Thus, there is a study of secondarily utilizing frequencychannels. As one example, there is a study of secondarily utilizing whatis called “television white space (TVWS)” with respect to televisionbroadcasting. Also, as another example, there is a study for allowing abase station of small cell to utilize a frequency channel for a basestation of macro cell in HetNet (Heterogeneous Network).

Several methods are conceived as a method in which a communication node,such as a master white space device (WSD) that secondarily utilizes aTVWS and a base station of small cell, utilizes a frequency channel. Forexample, as a first method, it is conceived to utilize a vacant channelthat is not utilized. Also, as a second method, it is conceived toprotect a main user of a primary system (for example, a televisionbroadcast system), a base station of macro cell, and the like by somesort of means, and to utilize an adequate frequency channel in theentire frequency channels including the utilized frequency channel.

As one example of the above first method, for example, Patent Literature1 discloses a technology in which the channel of TVWS is selected foreach time period on the basis of channel vacancy information for eachtime period corresponding to position information, and wirelesscommunication is performed on the basis of the selected channel of TVWS.

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2012-134650A

SUMMARY OF INVENTION Technical Problem

However, the technology disclosed in Patent Literature 1 is an exampleof the above first method, and therefore the utilized frequency channelis limited to a vacant channel that is not utilized by a main user (aprimary system, a base station of macro cell, etc.). Hence, thecommunication capacity of a communication node (a master WSD, a basestation of small cell, etc.) that utilizes a frequency channel canbecome smaller. Also, if a communication node (a master WSD, a basestation of small cell, etc.) tries to utilize a frequency channelutilized by the main user, the interference due to the utilization ofthe main user, which is not a control target, can occur in the abovecommunication node. Hence, the communication quality of thecommunication node can decrease.

Also, the technology disclosed in Patent Literature 1 does not consideran interference between a plurality of communication nodes (a pluralityof master WSDs, a plurality of base stations of small cell, etc.) thatutilize a frequency channel.

Hence, the communication quality of the plurality of communication nodescan decrease, in an environment in which an interference between theplurality of communication nodes can occur. In consideration of theinterference between the plurality of communication nodes, it isconceived to solve an optimization problem of a combination of theplurality of communication nodes and a plurality of frequency channelcandidates, for example. However, this is what is called a NP-hardproblem, and its solution is not calculated uniquely. Hence, full searchfor combinations of a plurality of communication nodes and a pluralityof frequency channel candidates is forced to be performed. The number ofthe combinations increases in an exponential fashion according to thenumber of the communication nodes and the number of the frequencychannel candidates, and therefore the calculation amount can becomeenormous.

Thus, it is desirable to provide a scheme that improves thecommunication of a communication node that utilizes a radio resource(frequency channel) under an environment in which there is aninterference from communication involving a communication node that isnot control target, with less calculation amount.

Solution to Problem

According to the present disclosure, there is provided a communicationcontrol device including: an acquisition unit configured to acquirefirst interference information indicating a first interference fromcommunication involving a communication node that is not control targetand second interference information indicating a second interferencefrom communication involving another communication node of controltarget, with respect to each of a plurality of communication nodes ofcontrol target; and a classifying unit configured to classify theplurality of communication nodes into a plurality of groups related to adecision of a radio resource that a communication node is able toutilize, on the basis of the first interference information and thesecond interference information with respect to the plurality ofcommunication nodes.

According to the present disclosure, there is provided a communicationcontrol method including: acquiring first interference informationindicating a first interference from communication involving acommunication node that is not control target and second interferenceinformation indicating a second interference from communicationinvolving another communication node of control target, with respect toeach of a plurality of communication nodes of control target; andclassifying the plurality of communication nodes into a plurality ofgroups related to a decision of a radio resource that a communicationnode is able to utilize, on the basis of the first interferenceinformation and the second interference information with respect to theplurality of communication nodes.

According to the present disclosure, there is provided an informationprocessing apparatus including: a memory that stores a predeterminedprogram; and a processor configured to execute the predeterminedprogram. The predetermined program is a program for executing acquiringfirst interference information indicating a first interference fromcommunication involving a communication node that is not control targetand second interference information indicating a second interferencefrom communication involving another communication node of controltarget, with respect to each of a plurality of communication nodes ofcontrol target, and classifying the plurality of communication nodesinto a plurality of groups related to a decision of a radio resourcethat a communication node is able to utilize, on the basis of the firstinterference information and the second interference information withrespect to the plurality of communication nodes.

Advantageous Effects of Invention

As described above, the present disclosure improves communication of acommunication node that utilizes a radio resource (frequency channel)under an environment in which there is an interference fromcommunication involving a communication node that is not control target,with less calculation amount.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram illustrating an example of a schematicconfiguration of a communication system according to an embodiment of apresent disclosure.

FIG. 2 is an explanatory diagram for describing an example of wirelesscommunication by a master WSD.

FIG. 3 is a sequence diagram for describing an example of a flow ofinformation in a communication system according to an embodiment of thepresent disclosure.

FIG. 4 is an explanatory diagram for describing an example of a locationrelationship between a primary system and a secondary system.

FIG. 5 is an explanatory diagram for describing a first example of adecision of an utilizable frequency channel with respect to each masterWSD.

FIG. 6 is an explanatory diagram for describing a second example of adecision of an utilizable frequency channel with respect to each masterWSD.

FIG. 7 is a block diagram illustrating an example of a configuration ofa communication control device according to a first embodiment.

FIG. 8 is an explanatory diagram for describing an example of a group ofmaster WSDs which are decided.

FIG. 9 is an explanatory diagram for describing an example of a positionof a slave WSD assumed when estimating an interference by an uplinksignal.

FIG. 10 describes a communication control process according to the firstembodiment.

FIG. 11 is a flowchart illustrating an example of a schematic flow of acommunication control process according to a first exemplary variant ofthe first embodiment.

FIG. 12 is an explanatory diagram for describing an example of acommunication system operated in another region adjacent to a region inwhich a communication system is operated.

FIG. 13 is an explanatory diagram for describing an example of a masterWSD included in a communication system according to a second embodiment.

FIG. 14 is a block diagram illustrating an example of a configuration ofa communication control device according to the second embodiment.

FIG. 15 is a flowchart illustrating an example of a schematic flow of acommunication control process according to the second embodiment.

FIG. 16 is a flowchart illustrating an example of a schematic flow of afrequency channel deciding process with respect to a low priority masterWSD.

FIG. 17 is an explanatory diagram for describing an application exampleof an embodiment of the present disclosure.

FIG. 18 is a block diagram illustrating an example of a schematicconfiguration of a server.

DESCRIPTION OF EMBODIMENTS

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. Notethat, in this specification and the drawings, elements that havesubstantially the same function and structure are denoted with the samereference signs, and repeated explanation is omitted.

Note that description will be made in the following order.

1. Configuration of Communication System

2. First Embodiment

2.1. Function and Configuration of Communication Control Device

2.2. Flow of Process

2.3. First Exemplary Variant

2.4. Second Exemplary Variant

2.5. Third Exemplary Variant

3. Second Embodiment

3.1. Overview

3.2. Function and Configuration of Communication Control Device

3.3. Flow of Process

4. Application Example

5. Specific Example of Communication Control Device

6. Conclusion

1. SCHEMATIC CONFIGURATION OF COMMUNICATION SYSTEM

First, with reference to FIGS. 1 to 6, the schematic configuration of acommunication system 1 according to an embodiment of the presentdisclosure will be described. FIG. 1 is an explanatory diagramillustrating an example of the schematic configuration of thecommunication system 1 according to the embodiment of the presentdisclosure. Referring to FIG. 1, the communication system 1 includes amaster WSD 10, a database (hereinafter, referred to as “DB”) 50, and acommunication control device 100. As described above, the communicationsystem 1 according to the present embodiment is a secondary system thatsecondarily utilizes a TVWS, for example.

(Master WSD 10)

The master WSD 10 is a communication node of the secondary system (thecommunication system 1) that secondarily utilizes a frequency channelfor a primary system (a television broadcast system). That is, themaster WSD 10 communicates wirelessly by secondarily utilizing thefrequency channel for the primary system (the television broadcastsystem).

For example, the master WSD 10 plays a role as an access point, and aslave WSD 30 accesses the master WSD 10. Then, the master WSD 10communicates wirelessly with the slave WSD 30. In the following, aspecific example will be described with reference to FIG. 2 with respectto this point.

FIG. 2 is an explanatory diagram for describing an example of wirelesscommunication by the master WSD 10. Referring to FIG. 2, the master WSD10 and a communication range 20 of the master WSD 10 are illustrated.When the slave WSD 30 is positioned in the communication range 20, themaster WSD 10 communicates wirelessly with the slave WSD 30. Here, themaster WSD 10 communicates wirelessly by secondarily utilizing thefrequency channel for the primary system. An example illustrated in FIG.2 is an example in which the master WSD 10 communicates wirelessly withone slave WSD 30, and the master WSD 10 can communicate wirelessly witha plurality of slave WSDs 30.

Also, for example, one or more master WSDs 10 form a set 40 of themaster WSDs 10. The set 40 is a set of the master WSDs 10 that canaffect each other, for example.

Also, for example, the master WSD 10 may employ time division duplex(TDD) or may employ frequency division duplex (FDD), as a duplex method.That is, the master WSD 10 communicates wirelessly by TDD or FDD.

Also, for example, allocation of the frequency channel to each slave WSD30 is performed by the master WSD 10 or the communication control device100. Specifically, for example, when TDD is employed, the master WSD 10may allocate a frequency channel to each slave WSD 30 and notify eachslave WSD 30 of the allocated frequency channel. Also, for example, whenFDD is employed, the communication control device 100 may allocate afrequency channel to each slave WSD 30, and each slave WSD 30 may benotified of the allocated frequency channel via the master WSD 10.

Note that the frequency channel that each master WSD 10 is able toutilize is decided by the communication control device 100, for example.

Also, the master WSD 10 is connected to the DB 50 and/or thecommunication control device 100 via a wired or wireless backhaul line,for example.

(DB 50)

The DB 50 collects and retains various information. For example, the DB50 collects and retains various types of information for deciding autilizable frequency channel with respect to each master WSD 10. Forexample, the DB 50 collects various types of information from the masterWSDs 10, the communication control device 100, a regulatory database(hereinafter, referred to as “regulatory DB”), and/or othercommunication nodes. The above regulatory DB is a DB included in aregulation institution of a country or an area, for example.

Information Relevant to Primary System

For example, the DB 50 collects information relevant to the primarysystem (the television broadcast system). More specifically, forexample, the information relevant to the primary system includesinformation (for example, number, position, height of antenna,transmission electric power) relevant to the communication node (thetransmitter station) of the primary system. Also, the informationrelevant to the primary system includes information (number of channels,channel band width, center frequency, permissible maximum transmissionelectric power of each channel, transmit spectrum mask, etc.) relevantto the frequency channels for the primary system. Also, the informationrelevant to the primary system includes information relevant to asecondarily utilizable channel among the frequency channels for theprimary system, for example. For example, the utilizable channelincludes a vacant channel that is not utilized. Also, for example, theutilizable channel includes a utilized channel that is secondarilyutilizable with prerequisite protection of the primary system.

Note that the DB 50 may collect information indicating an interferencefrom communication involving the communication node of the primarysystem, with respect to each master WSD 10, as the above informationrelevant to the primary system. The interference may be an interferencethat is actually observed, or may be an interference calculated as atheoretical value from path-loss and the like.

Also, for example, the DB 50 collects information relevant to theprimary system in a region under control of the DB 50, as the aboveinformation relevant to the primary system.

Note that the DB 50 may also collect information relevant to the primarysystem in another region adjacent to the region under control of the DB50, as the above information relevant to the primary system.

Also, for example, the DB 50 collects the above information relevant tothe primary system from the regulatory DB.

Information Relevant to Secondary System

Also, for example, the DB 50 collects information relevant to thesecondary system. More specifically, for example, information (forexample, number, position, height of antenna, transmission electricpower) relevant to the master WSD 10 of the secondary system isincluded.

Note that the DB 50 may also collect information indicating aninterference from communication involving another master WSD 10, withrespect to each master WSD 10, as the above information relevant to thesecondary system. The interference may be an interference that isactually observed, or may be an interference calculated in advance as atheoretical value from path-loss and the like.

Also, for example, the DB 50 collects information relevant to thesecondary system in a region under control of the DB 50, as the aboveinformation relevant to the secondary system.

Note that the DB 50 may also collect information relevant to thesecondary system in another region adjacent to the region under controlof the DB 50, as the above information relevant to the secondary system.

Also, for example, the DB 50 collects or in advance retains the aboveinformation relevant to the secondary system from the master WSD.

Others

Also, for example, the DB 50 acquires parameters necessary for referringto an interference electric power. The parameters include an adjacentchannel leakage ratio (ACLR), an adjacent channel selectivity (ACS), ashadowing margin, a fading margin, and/or a protection ratio (PR), forexample.

Also, the DB 50 may collect the information of a position of a boundaryline between a region under control of the DB 50 and another regionadjacent to this region.

As described above, the DB 50 collects and saves various information.Note that, when the primary system and the secondary system continuouslyexist from the past, and the DB 50 already retains the informationrelevant to these primary system and secondary system, the DB 50 mayutilize the information that is retained already. Also, the DB 50 maycollect and update the information, when the information that isretained already is changed.

(Communication Control Device 100)

The communication control device 100 executes various processes relevantto control of the master WSD 10. For example, the processes include aprocess relevant to decision of a utilizable frequency channel withrespect to each master WSD 10.

For example, the communication control device 100 decides the utilizablefrequency channel with respect to each master WSD 10 of control target.Here, the communication control device 100 considers a firstinterference from communication involving the communication node that isnot control target (for example, the communication node of the primarysystem), and a second interference from communication involving anothermaster WSD 10 of control target.

(Flow of Information in Communication System)

With reference to FIG. 3, an example of flow of information in thecommunication system 1 will be described. FIG. 3 is a sequence diagramfor describing an example of the flow of the information in thecommunication system 1 according to the embodiment of the presentdisclosure.

The regulatory DB provides the DB 50 with the information relevant tothe primary system (S1001).

Also, the DB 50 notifies the master WSD 10 of an update of information(S1003). Then, the master WSD 10 provides the DB 50 with the informationnecessary for the decision of the utilizable frequency channel (S1005).

Further, the DB 50 provides the communication control device 100 withthe information necessary for the decision of the utilizable frequencychannel (S1007). Then, the communication control device 100 decides theutilizable frequency channel with respect to each master WSD 10 (S1009).

Then, the communication control device 100 notifies each master WSD 10of the decided utilizable frequency channel (S1011). Then, each masterWSD 10 communicates wirelessly by utilizing the utilizable frequencychannel.

Also, the communication control device 100 notifies the DB 50 of thedecided utilizable frequency channel (S1013). Then, the DB 50 stores theutilizable frequency channel with respect to each master WSD.

(Location Example of Primary System and Secondary System)

With reference to FIG. 4, an example of the location relationshipbetween a television broadcast system which is the primary system andthe communication system 1 which is the secondary system will bedescribed.

FIG. 4 is an explanatory diagram for describing an example of thelocation relationship between the primary system and the secondarysystem. Referring to FIG. 4, the master WSD 10, the slave WSD 30, the DB50, and the communication control device 100 of the communication system1 which is the secondary system are illustrated. Also, a transmitterstation 60 and reception terminals 70 of the television broadcast systemwhich is the primary system are illustrated. A prohibition area 61 inwhich secondary utilization of TVWS is prohibited, a protection area 63for protecting the primary system, and a utilizable area 65 in whichsecondary utilization of TVWS is permitted are set. Then, the master WSD10 is located in the utilizable area 65.

(Decision of Utilizable Frequency Channel)

As described above, in the communication system 1 which is the secondarysystem, the utilizable frequency channel is decided with respect to eachmaster WSD 10. In the following, with reference to FIGS. 5 and 6, aspecific example of an example of the decision of the utilizablefrequency channel with respect to each master WSD 10 will be described.

FIG. 5 is an explanatory diagram for describing the first example of thedecision of the utilizable frequency channel with respect to each masterWSD 10. Referring to FIG. 5, frequency channels f₁ to f₅ for the primarysystem is illustrated. In this example, the frequency channel f₂ isdecided as the utilizable frequency channel with respect to a set 40A ofthe master WSDs 10. Also, the frequency channel f₂ further includesfrequency channels f_(2A) to f_(2E). Then, one or more frequencychannels of the frequency channels f_(2A) to f_(2E) are decided as theutilizable frequency channels, with respect to each master WSD 10included in the set 40A. Also, the frequency channel ft is decided asthe utilizable frequency channel with respect to a set 40B of the masterWSDs 10. Also, the frequency channel ft further includes frequencychannels f_(4A) to f_(4E). Then, one or more frequency channels of thefrequency channels f_(4A) to f_(4E) are decided as the utilizablefrequency channels with respect to each master WSD 10 included in theset 40B.

Although, in the example in FIG. 5, the utilizable frequency channelswith respect to the set 40A and the utilizable frequency channels withrespect to the set 40B are different frequency channels, these frequencychannels may be same frequency channels.

FIG. 6 is an explanatory diagram for describing the second example ofthe decision of the utilizable frequency channel with respect to eachmaster WSD 10. Referring to FIG. 5, the frequency channels f₁ to f₅ forthe primary system are illustrated. In this example, the utilizablefrequency channel with respect to each set 40 is not decided, but theutilizable frequency channel with respect to each master WSD 40 isdirectly decided.

2. FIRST EMBODIMENT

Next, with reference to FIGS. 7 to 12, the first embodiment of thepresent disclosure will be described. The first embodiment of thepresent disclosure improves communication of a communication node thatutilizes a radio resource (frequency channel) under an environment inwhich there is an interference from communication involving acommunication node that is not control target, with less calculationamount.

<2.1. Function and Configuration of Communication Control Device>

With reference to FIGS. 7 to 9, an example of a configuration of acommunication control device 100-1 according to the first embodimentwill be described. FIG. 7 is a block diagram illustrating an example ofthe configuration of the communication control device 100-1 according tothe first embodiment. Referring to FIG. 7, the communication controldevice 100-1 includes a communication unit 110, a storage unit 120, anda control unit 130.

(Communication Unit 110)

The communication unit 110 communicates with other devices. For example,the communication unit 110 communicates with the DB 50 and the masterWSD 10.

(Storage Unit 120)

The storage unit 120 stores programs and data for the operation of thecommunication control device 100-1. For example, the storage unit 120stores information acquired from the DB 50.

(Control Unit 130)

The control unit 130 provides various function of the communicationcontrol device 100-1. The control unit 130 includes a set deciding unit131, an interference estimating unit 133, an interference informationacquiring unit 135, a classifying unit 137, and a channel deciding unit139.

(Set Deciding Unit 131)

The set deciding unit 131 decides the set 40 of the master WSDs 10.

As described above, for example, the set 40 is a set of the master WSDs10 that can affect each other. For example, the master WSD 10 includedin the set 40 interferes with another one of the master WSDs 10 includedin the set 40. In this case, the set deciding unit 131 acquiresinformation relevant to each master WSD 10 included in the communicationsystem 1 (for example, number, position, height of antenna, transmissionelectric power) from the DB 10 via the communication unit 110. Then, theset deciding unit 131 decides the set 40 of the master WSDs 10, on thebasis of the acquired information.

As described above, as one example, the set 40 is a set of the masterWSDs 10 positioned at a vicinity. In this case, the set deciding unit131 identifies the master WSDs 10 around each master WSD, on the basisof the position of each master WSD 10 included in the communicationsystem 1. Then, the set deciding unit 131 determines whether or not eachmaster WSD has a large influence on the master WSD 10 nearby. Then, theset deciding unit 131 decides the set 40 of the master WSDs 10, on thebasis of the determination result. In the following, with reference toFIG. 8, an example of a set of the master WSDs 10 which is decided willbe described.

FIG. 8 is an explanatory diagram for describing an example of a set ofthe master WSDs 10 which is decided. Referring to FIG. 8, for example, aplurality of master WSDs 10A that exist densely are decided as the set40A. Also, a plurality of other master WSDs 10B that exist densely aredecided as the set 40B. On the other hand, another master WSD 10 doesnot exist around a master WSD 10C, and therefore any set is not decidedwith regard to the master WSD 10C.

(Interference Estimating Unit 133)

The interference estimating unit 133 estimates the interference withrespect to each of a plurality of master WSDs 10 of control target. Eachof the plurality of the master WSDs 10 is the master WSD 10 of thecommunication system 1 which is the secondary system that secondarilyutilizes the frequency channel for the primary system. For example, theabove plurality of master WSDs 10 are the master WSDs 10 included in thesame set 40, and the interference estimating unit 133 estimates theabove interference for each decided set 40.

First Interference from Communication Involving Communication Node Thatis Not Control Target

First, the interference estimating unit 133 estimates a firstinterference from communication involving the communication node that isnot control target, with respect to each of the above plurality ofmaster WSDs 10.

Communication Node that is not Control Target

For example, the communication node that is not the above control targetincludes a communication node that is not control target by thecommunication control device 100-1.

More specifically, for example, the communication node that is not theabove control target includes a communication node of the primarysystem. That is, as an example of the embodiment of the presentdisclosure, the communication node that is not the above control targetincludes a transmitter station of the television broadcast system.

Interference

The above first interference is an interference by a downlink signaltransmitted by the communication node that is not the above controltarget or an uplink signal transmitted to the communication node that isnot the above control target. For example, the above first interferenceincludes an interference by a downlink signal transmitted by thetransmitter station of the television broadcast system.

Also, for example, the above first interference is an interference tocommunication involving the master WSD 10. More specifically, the abovefirst interference is an interference to the uplink communication (thetransmission to the master WSD 10 from the slave WSD 30) and/or aninterference to the downlink communication (the transmission to theslave WSD 30 from the master WSD 10). In other words, the above firstinterference is an interference to the uplink signal received by themaster WSD 10 (the transmission signal of the slave WSD 30) and/or aninterference to the downlink signal received by the slave WSD 30 (thetransmission signal of the master WSD 10).

As one example, the above first interference is an interference to theuplink communication (i.e., an interference to the uplink signal).Thereby, there is a larger interference to communication involving themaster WSD 10. Also, interference is estimated more easily.

Specifically, the antenna of the master WSD 10 is normally at a higherposition than the position of the antenna of the slave WSD 30, andtherefore the master WSD 10 is affected by the communication node of theprimary system (the transmitter station of the television broadcastsystem) more significantly than the slave WSD 30 is. That is, theinterference to the uplink communication is larger than the interferenceto the downlink communication. Hence, a larger interference to thecommunication involving the master WSD 10 is obtained, by estimating theinterference to the uplink communication as the above firstinterference.

Also, the master WSD 10 that receives the uplink signal has a lowermobility than the slave WSD 30 that receives the downlink signal. As oneexample, the position of the slave WSD 30 can be changed frequently,while the position of the master WSD 10 is fixed. Hence, the master WSD10 can estimate the interference more easily.

Estimation of Interference Estimation of Interference of Each FrequencyChannel Candidate

The interference estimating unit 133 estimates the above firstinterference in each of two or more frequency channel candidates, withrespect to each of the above plurality of master WSDs 10. The two ormore frequency channel candidates are the frequency channels that thecommunication system 1 is able to utilize secondarily, among thefrequency channels for the primary system.

Estimation of Electric Power Value

Also, the interference estimating unit 133 estimates a receptionelectric power value of the interference signal for example, as theabove first interference. For example, the electric power value of theinterference from communication involving the communication node of theprimary system (i.e., the reception electric power value of thetransmission signal (interference signal) of the transmitter station ofthe television broadcast system, in the master WSD 10) is expressed asin the following.P _(I,Primary,n)(f)  [Math. 1]

Here, n represents an index of the master WSD 10 of target forestimating an interference, among the above plurality of master WSDs 10.Also, f represents one frequency channel candidate among a plurality offrequency channel candidates.

Note that the interference estimating unit 133 acquires parameters thatare necessary for referring to the information relevant to the primarysystem, the information relevant to the secondary system, and theinterference electric power, from the DB 50 via the communication unit110, for example. Then, the interference estimating unit 133 estimatesthe above first interference, on the basis of the acquired information.As described above, the information relevant to the primary systemincludes the information relevant to the communication node (thetransmitter station) of the primary system (e.g., number, position,height of antenna, transmission electric power), for example. Also, asdescribed above, the information relevant to the secondary systemincludes, the information relevant to the master WSD 10 of the secondarysystem (for example, number, position, height of antenna, transmissionelectric power), for example.

Second Interference from Communication Involving Another CommunicationNode of Control Target

Second, the interference estimating unit 133 estimates the secondinterference from communication involving another communication node ofcontrol target, with respect to each of the above plurality of masterWSDs 10 of control target.

Another Communication Node of Control Target

For example, the above other communication node of control target is acommunication node which is control target by the communication controldevice 100-1.

More specifically, for example, the above other communication nodeincludes another master WSDs 10 that are not the master WSD 10 for whichthe interference is estimated, among the above plurality of master WSDs10. As one example, the above other communication node includes anothermaster WSD 10 that is not the master WSD 10 for which the interferenceis estimated and is included in the same set 40 as the master WSD 10 forwhich the interference is estimated, among the above plurality of masterWSDs 10.

Interference

The above second interference is an interference by the downlink signaltransmitted by the above other communication node or the uplink signaltransmitted to the above other communication node. For example, theabove second interference includes an interference by the downlinksignal transmitted by another master WSD 10 that is not the master WSDfor which the interference is estimated, or an interference by theuplink signal transmitted to another master WSD 10 that is not themaster WSD for which the interference is estimated.

Also, for example, the above second interference is an interference tocommunication involving the master WSD 10. More specifically, the abovesecond interference is an interference to the uplink communication (thetransmission to the master WSD 10 from the slave WSD 30) and/or aninterference to the downlink communication (the transmission to theslave WSD 30 from the master WSD 10). In other words, the above secondinterference is an interference to the uplink signal received by themaster WSD 10 (the transmission signal of the slave WSD 30) and/or aninterference to the downlink signal received by the slave WSD 30 (thetransmission signal of the master WSD 10).

As one example, the above second interference is an interference to theuplink communication (i.e., an interference to the uplink signal).Thereby, there is a larger interference to communication involving themaster WSD 10. Also, interference is estimated more easily.

Estimation of Interference Estimation of Interference of Each FrequencyChannel Candidate

The interference estimating unit 133 estimates the above secondinterference in each of the two or more frequency channel candidates,with respect to each of the above plurality of master WSDs 10. The twoor more frequency channel candidates is a frequency channel that thecommunication system 1 is able to utilize secondarily, among thefrequency channels for the primary system. Also, here, the above two ormore frequency channel candidates are two or more frequency channelcandidates. That is, the above second interference in each of the two ormore frequency channel candidates is estimated.

Provisional Setting of Frequency Channel

Also, for example, the interference estimating unit 133 provisionallysets the frequency channel utilized by each of a plurality of masterWSDs 10 of control target, to calculate the above second interference.

Specifically, for example, the frequency channel utilized immediatelybefore is set provisionally. For example, when a certain communicationnode utilizes a certain frequency channel immediately before, thecertain frequency channel is set provisionally in the certaincommunication node. Also, when another communication node utilizesanother frequency channel immediately before, the other frequencychannel is set provisionally in the other communication node.

Note that it may be such that the provisionally set frequency channel isnot the frequency channel utilized immediately before, but a frequencychannel for which the interference from the primary system is small, afrequency channel selected on the basis of a result of measurement orsensing, a frequency channel selected at random, or the like.

Estimation of Interference in Individual Frequency Channels

Also, the above second interference in the individual frequency channelcandidates is estimated by estimating the interference fromcommunication involving each of the above other communication nodes ofcontrol target (other master WSDs 10) first, and summing theinterference estimated with respect to each of the above othercommunication node.

For example, the interference from the communication involving each ofother master WSDs 10 of control target is any one of the followings.

(1) An interference from transmission only of the master WSD 10 (aninterference by the downlink signal only)

(2) An interference from transmission only of the slave WSD 30 (aninterference by the uplink signal only)

(3) An interference from the transmission of the master WSD 10 and thetransmission of the slave WSD 30 (an interference by the downlink signaland the uplink signal)

The interference of above (1) is an interference when the master WSD 10performs the downlink communication only. For example, the interferenceestimating unit 133 can estimate the interference of above (1) on thebasis of information relevant to the master WSD 10 (position, height ofantenna, transmission electric power, etc.) and information ofprovisional setting of the frequency channel.

The interference of above (2) is an interference when the master WSD 10performs the uplink communication only. For example, the interferenceestimating unit 133 suppositionally sets information relevant to theslave WSD 30 (position, height of antenna, transmission electric power,etc.), and estimates the interference of above (2) on the basis of thesuppositionally set information and the information of the provisionalsetting of the frequency channel.

The interference of above (3) is an interference when the master WSD 10performs both of the uplink communication and the downlinkcommunication. The frequency channel candidates for the uplinkcommunication and the frequency channel candidates for the downlinkcommunication are different frequency channel candidates in some cases(for example, in the case of FDD), and are same frequency channels inother cases (for example, in the case of TDD). In the former case, theinterference estimating unit 133 estimates the interference from thedownlink communication (the interference by the downlink signal) in thesame way as the interference of above (1), and estimates theinterference from the uplink communication (the interference by theuplink signal) in the same way as the interference of above (2), andsums the estimated interferences. Also, in the latter case, theinterference estimating unit 133 estimates the interference from one ofthe downlink communication and the uplink communication. Note that, inthe latter case, for example, the interference estimating unit 133estimates the interference from the downlink communication (theinterference by the downlink signal) and the interference from theuplink communication (the interference by the uplink signal), andselects the larger one. By this selection, a larger interference to thecommunication involving the master WSD 10 is estimated.

Note that, as described above, when the interference from thetransmission of the slave WSD 30 (the interference by the uplink signal)is estimated, the information relevant to the slave WSD 30 (position,height of antenna, transmission electric power, etc.) is suppositionallyset. In this case, for example, the slave WSD 30 is assumed to exist ina predetermined range or at a predetermined position closer to themaster WSD 10 for which the interference is estimated, within thecommunication range 20 of the master WSD 10 which is the transmissiondestination of the uplink signal of the slave WSD 30. Then, theinterference estimating unit 133 estimates the interference by theuplink signal, under this assumption. In the following, a specificexample will be described with reference to FIG. 9, with respect to thispoint.

FIG. 9 is an explanatory diagram for describing an example of theposition of the slave WSD 30 which is suppositionally set whenestimating the interference by the uplink signal. Referring to FIG. 9,the master WSDs 10-1 to 10-5 are illustrated. In this example, theinterference to the uplink communication of the master WSD 10-1 isestimated. In this case, for example, the slave WSD 30 that transmitsthe uplink signal to the master WSD 10-2 is assumed to be positioned atthe position 41-2 closest to the master WSD 10-1, within thecommunication range 20-2 of the master WSD 10-2. Also, the slave WSD 30that transmits the uplink signal to the master WSD 10-5 is assumed to bepositioned at the position 41-5 closest to the master WSD 10-1 withinthe communication range 20-5 of the master WSD 10-5.

By this assumption, a larger interference to the communication involvingthe master WSD 10 is obtained.

Estimation of Electric Power Value

Also, the interference estimating unit 133 estimates the receptionelectric power value of the interference signal for example, as theabove second interference. For example, the electric power value of theinterference from communication involving another master WSD 10 ofcontrol target (i.e., the reception electric power value of the downlinksignal from another master WSD 10 and/or the uplink signal to anothermaster WSD 10 (the interference signal), in the master WSD 10) isexpressed as in the following.P _(I,WSD,n)(f)  [Math. 2]

Here, n represents an index of the master WSD 10 of target forestimating an interference, among the above plurality of master WSDs 10.Also, f represents one frequency channel candidate among a plurality offrequency channel candidates.

Note that the interference estimating unit 133 acquires the informationrelevant to the secondary system, from the DB 50, via the communicationunit 110, for example. Also, as described above, the interferenceestimating unit 133 suppositionally sets the information relevant to theslave WSD 30 (position, height of antenna, transmission electric power,etc.). Then, the interference estimating unit 133 estimates the abovesecond interference, on the basis of the acquired information and/or thesuppositionally set information. As described above, the informationrelevant to the secondary system includes the information relevant tothe master WSD 10 of the secondary system (for example, number,position, height of antenna, transmission electric power), for example.

(Interference Information Acquiring Unit 135)

First Interference Information

The interference information acquiring unit 135 acquires the firstinterference information indicating the first interference fromcommunication involving the communication nodes that are not controltarget, with respect to each of a plurality of master WSDs 10 of controltarget. For example, the above plurality of master WSDs 10 are themaster WSDs 10 included in the same set 40, and the interferenceestimating unit 133 acquires the above first interference informationfor each decided set 40.

As described above, for example, the communication nodes that are notthe above control target include the communication nodes that are notcontrol target by the communication control device 100-1. Morespecifically, for example, the communication nodes that are not theabove control target include the communication nodes of the primarysystem. That is, as an example of the embodiment of the presentdisclosure, the communication nodes that are not the above controltarget include the transmitter station of the television broadcastsystem.

Also, for example, the above first interference information indicatesthe above first interference in each of the two or more frequencychannel candidates. As described above, the above two or more frequencychannel candidates are frequency channels that the communication system1 is able to utilize secondarily, among the frequency channels for theprimary system. Also, here, the above two or more frequency channelcandidates are two or more frequency channel candidates. That is, thefirst interference information indicates the above first interference ineach of the above two or more frequency channel candidates.

For example, the interference information acquiring unit 135 acquiresthe information indicating the first interference estimated by theinterference estimating unit 133, as the first interference information.

Note that the interference information acquiring unit 135 may acquirethe information indicating the first interference that is actuallyobserved, or the information indicating the first interferencecalculated in advance as the theoretical value from path-loss and thelike (i.e., the information store in the DB 50), as the firstinterference information, instead of the information indicating thefirst interference estimated by the interference estimating unit 133. Inthis case, the first interference is needless to be estimated by theinterference estimating unit 133 as described above.

Second Interference Information

Also, the interference information acquiring unit 135 acquires thesecond interference information indicating the second interference fromcommunication involving another communication node of control target,with respect to each of a plurality of master WSDs 10 of control target.For example, the above plurality of master WSDs 10 are the master WSDs10 included in the same set 40, and the interference estimating unit 133acquires the above second interference information for each decided set40.

As described above, for example, the above other communication node ofcontrol target is the communication node which is control target by thecommunication control device 100-1. More specifically, for example, theabove other communication node includes another master WSDs 10 that arenot the master WSD 10 for which the interference is estimated, among theabove plurality of master WSDs 10.

Also, for example, the above second interference information indicatesthe above second interference in each of the above two or more frequencychannel candidates. As described above, the above two or more frequencychannel candidates are frequency channels that the communication system1 is able to utilize secondarily, among the frequency channels for theprimary system. Also, here, the above two or more frequency channelcandidates are two or more frequency channel candidates. That is, thesecond interference information indicates the above second interferencein each of the above two or more frequency channel candidates.

For example, the interference information acquiring unit 135 acquiresthe information indicating the second interference estimated by theinterference estimating unit 133, as the second interferenceinformation.

Note that the interference information acquiring unit 135 may acquirethe information indicating the second interference that is actuallyobserved, or the information indicating the second interferencecalculated in advance as the theoretical value from path-loss and thelike (i.e., the information store in the DB 50), as the secondinterference information, instead of the information indicating thesecond interference estimated by the interference estimating unit 133.In this case, the second interference is needless to be estimated by theinterference estimating unit 133 as described above.

(Classifying Unit 137)

The classifying unit 137 classifies the above plurality of master WSDs10 into a plurality of groups related to the decision of the frequencychannel that the master WSD 10 is able to utilize, on the basis of theabove first interference information and the above second interferenceinformation with respect to the above plurality of master WSDs 10 ofcontrol target. Also, for example, the above plurality of master WSDs 10are the master WSDs 10 included in the same set 40, and the classifyingunit 137 classifies the master WSDs 10 for each decided set 40.

Also, for example, the above plurality of groups are a plurality ofgroups corresponding to the order in which the above frequency channelsare decided. More specifically, for example, the above plurality ofgroups include at least a first group and a second group. The abovesecond group is a group in which the above frequency channels aredecided after the above first group or before the first group. Theclassifying unit 137 classifies the above plurality of master WSDs intoa plurality of groups including the above first group and the abovesecond group. As one example, the classifying unit 137 classifies theabove plurality of master WSDs 10 into the two groups of the above firstgroup and the above second group.

Also, for example, the master WSDs 10 classified into the above firstgroup is the master WSD 10 having a larger level of the above firstinterference relative to the above second interference, as compared withthe master WSD 10 classified into the above second group. That is, theclassifying unit 137 classifies the above plurality of master WSDs 10into a plurality of groups including the above first group and the abovesecond group, in such a manner that the master WSDs 10 classified intothe above first group has a larger level of the above first interferencerelative to the above second interference, as compared with the masterWSD 10 classified into the above second group. As one example, theclassifying unit 137 classifies, into the first group, the master WSD 10having a larger level of the above first interference relative to theabove second interference, among the above plurality of master WSDs 10.Also, the classifying unit 137 classifies, into the second group, themaster WSD 10 having a smaller level of the above first interferencerelative to the above second interference, among the above plurality ofmaster WSDs 10.

Also, for example, the above second group is a group in which the abovefrequency channels are decided after the above first group. In thiscase, as one example, the classifying unit 137 classifies, into thefirst group in which the utilizable frequency channels are firstdecided, the master WSD 10 having a larger level of the above firstinterference relative to the above second interference, among the aboveplurality of master WSDs 10. Also, the classifying unit 137 classifies,into the second group in which the utilizable frequency channels aredecided later, the master WSD 10 having a smaller level of the abovefirst interference relative to the above second interference, among theabove plurality of master WSDs 10.

By this classification, for example, the utilizable frequency channelswith respect to the master WSD 10 having a comparatively weakinterference in the secondary system relative to the interference fromthe primary system are decided first. Then, the utilizable frequencychannels with respect to the master WSD 10 having a comparatively stronginterference in the secondary system relative to the interference fromthe primary system are decided thereafter. That is, the utilizablefrequency channels with respect to the master WSD 10 having a smallerinfluence on the interference by the decision of the utilizablefrequency channels in the secondary system (for example, the fluctuationof the interference level) are decided first. Then, the utilizablefrequency channels with respect to the master WSD 10 having a largerinfluence on the interference by the decision of the utilizablefrequency channel in the secondary system (for example, the fluctuationof the interference level) are decided thereafter.

Hence, a more appropriate utilizable frequency channel is decided withrespect to the master WSD 10 having a larger influence of the decisionof the utilizable frequency channel in the secondary system, inconsideration of the utilizable frequency channels that are alreadydecided with respect to other master WSDs 10. On the other hand, withrespect to the master WSD 10 having a smaller influence of the decisionof the utilizable frequency channel in the secondary system, theinfluence (for example, the fluctuation of the interference level)occurs by the following decision of the utilizable frequency channelwith respect to other master WSDs 10, but the influence is small.Thereby, a more appropriate utilizable frequency channel with respect toeach master WSD 10 can be decided in the secondary system. As a result,the communication of the master WSD 10 that secondarily utilizes thefrequency channel can be improved.

Also, the utilizable frequency channel is decided in order for eachgroup (i.e., divided utilizable frequency channels with respect to themaster WSD 10 are decided in order), and therefore the number ofcombinations of the master WSD 10 and the frequency channel candidatedecreases. As a result, the calculation amount can be reduced.

As described above, communication of a communication node that utilizesa radio resource (frequency channel) under an environment in which thereis an interference from communication involving a communication nodethat is not control target is improved with less calculation amount.

Also, more specifically, for example, the above level of the above firstinterference relative to the above second interference corresponds tothe number of frequency channel candidates in which the level of theabove first interference is larger than the level of the above secondinterference by a predetermined threshold value or more. For example,the level of the above first interference and the level of the secondinterference is the reception electric power of the interference signalin the master WSD 10 that is subject to the interference. Then, theabove level of the above first interference relative to the above secondinterference corresponds to the number of frequency channel candidatesin which the level of the first interference (the reception electricpower of the interference signal) is larger than the level of the secondinterference (the reception electric power of the interference signal)by a predetermined threshold value. As one example, the above apredetermined threshold value is 0, and the above level is theproportion of the frequency channel candidates in which the level of thefirst interference is larger than the second interference. Then, theclassifying unit 137 classifies the master WSD 10 having the aboveproportion that exceeds a threshold value x (0<x<1), into the firstgroup in which the utilizable frequency channels are first decided.Also, the classifying unit 137 classifies the master WSD 10 having theabove proportion that is equal to or less than the threshold value x,into the second group in which the utilizable frequency channels aredecided later. That is, the classifying unit 137 classifies a pluralityof master WSDs 10 as in the following.

$\begin{matrix}{n \in \left\{ \begin{matrix}G^{1{st}} & {{{{if}\mspace{14mu}{card}{\left\{ {p❘{{P_{I,{Primary},n}(f)} > {P_{I,{WSD},n}(f)}}} \right\}/N_{Channel}}} > x},} \\G^{2{nd}} & {else}\end{matrix} \right.} & \left\lbrack {{Math}.\mspace{14mu} 3} \right\rbrack\end{matrix}$

Here, n represents an index of the master WSD 10 of the target to beclassified, among the above plurality of master WSDs 10. Also, G^(1st)indicates the first group, and G^(2nd) indicates the second group. Also,f represents one frequency channel candidate among a plurality offrequency channel candidates. N_(channel) indicates the number of thefrequency channel candidates (i.e., the number of the frequency channelsthat the communication system 1 is able to utilize). P indicates a setof frequency channels that satisfy P_(I,Primary,n)(f)>P_(I,WSD,n)(f).Then, card {• • • } is the cardinality of the set. When elements of theset is discrete, card {• • • } is equivalent to the number of theelements of the set (i.e., the number of the frequency channelcandidates). Also, as described above, x is a threshold value that islarger than 0 and smaller than 1.

This classification into the groups enables classifying the master WSD10 having a comparatively weak interference in the secondary systemrelative to the interference from the primary system, and the master WSD10 having a comparatively strong interference in the secondary systemrelative to the interference from the primary system.

(Channel Deciding Unit 139)

The channel deciding unit 139 decides the utilizable frequency channelwith respect to each of the above plurality of master WSDs 10 of controltarget. For example, the above plurality of master WSDs 10 are themaster WSDs 10 included in the same set 40, and the interferenceestimating unit 133 classifies the master WSDs 10 for each decided set40.

Decision in Order According to Group

For example, the channel deciding unit 139 decides the above frequencychannel with respect to each of one or more master WSDs 10 classifiedinto the above first group. Also, the channel deciding unit 139 decidesthe above frequency channel with respect to each of one or more masterWSDs 10 classified into the above second group, on the basis of thedecision result of the above frequency channel in the above first group.

Decision of Frequency Channel in First Group

As described above, the master WSDs 10 classified into the above firstgroup is the master WSD 10 having a larger level of the above firstinterference relative to the above second interference, as compared withthe master WSD 10 classified into the above second group.

For example, the channel deciding unit 139 decides one or more frequencychannel candidates having a smaller level of the above firstinterference, among the two or more frequency channel candidates, as theutilizable frequency channel with respect to the master WSDs 10classified into the above first group. The two or more frequency channelcandidates are the frequency channels that the communication system 1 isable to utilize secondarily, among the frequency channels for theprimary system.

This decision of the frequency channel reduces the interference from theprimary system in the master WSD 10 classified into the first group (forexample, the master WSD 10 having a comparatively strong interferencefrom the primary system relative to the interference in the secondarysystem), for example. Hence, the communication quality of the master WSD10 classified into the first group improves, and the communication ofthe master WSD can be improved. Note that this decision is effective, inparticular when there is a variation in the level of the interferencefrom the primary system by the frequency channel candidate.

Note that, as another example, the channel deciding unit 139 may decideone or more frequency channel candidates utilized by the master WSDs 10classified into the above first group, as the utilizable frequencychannel with respect to the master WSD 10. With this decision of thefrequency channel, the decision is needless to be made again, andtherefore the calculation amount is reduced. Note that this decision iseffective, in particular when there is little variation in the level ofthe interference from the primary system by the frequency channelcandidates.

Also, as yet another example, the channel deciding unit 139 may decideas the utilizable frequency channel with respect to the master WSDs 10classified into the above first group, by another method.

Decision of Frequency Channel in Second Group

As described above, the master WSD 10 classified into the above secondgroup is the master WSD 10 having a smaller level of the above firstinterference relative to the above second interference, as compared withthe master WSD 10 classified into the above second group.

As described above, for example, the channel deciding unit 139 decidesthe above frequency channel with respect to each of one or more masterWSDs 10 classified into the above second group, on the basis of thedecision result of the above frequency channel in the above first group.

Order of Decision of Frequency Channel

As described above, the channel deciding unit 139 decides the aboveresource (the frequency channel) with respect to each of the above oneor more master WSDs 10 classified into the above second group. Forexample, here, the channel deciding unit 139 decides the above frequencychannel with respect to the master WSD 10 having a smaller level of theabove second interference. Then, the channel deciding unit 139 decidesthe above frequency channel with respect to the master WSD 10 having alarger level of the above second interference, on the basis of thedecision result of the above frequency channel with respect to themaster WSD 10. That is, the channel deciding unit 139 decides theutilizable frequency channel with respect to the master WSD 10, in orderfrom the master WSD 10 having a smaller level of the secondinterference.

More specifically, for example, the channel deciding unit 139 decidesthe utilizable frequency channel, in order from the master WSD 10 havinga smaller maximum level of the level of the second interference in thetwo or more frequency channel candidates. For example, above the maximumlevel is, the maximum level of the electric power value of theinterference from communication involving another master WSD 10 ofcontrol target (i.e., the reception electric power value of theinterference signal) P_(I,WSD,n)(f) in the two or more frequency channelcandidates. The maximum level P_(I_MAX,WSD,n) is expressed as in thefollowing.

$\begin{matrix}{P_{{I\_ MAX},{WSD},n} = {\max\limits_{f}{P_{I,{WSD},n}(f)}}} & \left\lbrack {{Math}.\mspace{14mu} 4} \right\rbrack\end{matrix}$

As described above, for example, the channel deciding unit 139 decidesthe utilizable frequency channel in order from the smaller maximum levelP_(I_MAX,WSD,n). Then, for example, the channel deciding unit 139decides the utilizable frequency channel with respect to the k-th masterWSD 10, on the basis of the decision result with respect to the first tok−1th master WSDs 10. Also, for example, the channel deciding unit 139decides the utilizable frequency channel with respect to the k-th masterWSD 10, on the basis of the provisional setting result of the frequencychannel with respect to the k+1th and following master WSDs 10 as well.

By the decision in this order, the utilizable frequency channel withrespect to the master WSD 10 having a weaker interference in thesecondary system is decided first, for example. Then, the utilizablefrequency channel with respect to the master WSD 10 having a strongerinterference in the secondary system is decided thereafter. That is, theutilizable frequency channels with respect to the master WSD 10 having asmaller influence on the interference by the decision of the utilizablefrequency channels in the secondary system (for example, the fluctuationof the interference level) are decided first. Then, the utilizablefrequency channels with respect to the master WSD 10 having a largerinfluence on the interference by the decision of the utilizablefrequency channel in the secondary system (for example, the fluctuationof the interference level) are decided thereafter.

Hence, a more appropriate utilizable channel is decided with respect tothe master WSD 10 having a larger influence of the decision of theutilizable frequency channel in the secondary system, in considerationof the utilizable frequency channels that are already decided withrespect to other master WSDs 10. On the other hand, with respect to themaster WSD 10 having a smaller influence of the decision of theutilizable frequency channel in the secondary system, the influence (forexample, the fluctuation of the interference level) occurs by thefollowing decision of the utilizable frequency channel with respect toother master WSDs 10, but the influence is small. Thereby, a moreappropriate utilizable frequency channel with respect to each master WSD10 can be decided in the secondary system. As a result, thecommunication of the master WSD 10 that secondarily utilizes thefrequency channel can be improved.

Also, the utilizable frequency channels are decided one after anotherwith respect to each master WSD 10, and therefore the calculation amountcan be reduced.

Note that, as described above, the channel deciding unit 139 decides theutilizable frequency channel with respect to the k-th master WSD 10, onthe basis of the decision result of the frequency channel in the abovefirst group.

Decision of Frequency Channel

Also, for example, the channel deciding unit 139 decides one or morefrequency channel candidates among the two or more frequency channelcandidates, as the utilizable frequency channel with respect to themaster WSD 10 classified into the above second group. Then, the one ormore frequency channel candidates are one or more frequency channelcandidates having a smaller level of the interference, which include theabove first interference and the above second interference.

Specifically, for example, to decide the utilizable frequency channelwith respect to the k-th master WSD 10, the channel deciding unit 139acquires the knowledge of the level of the first interference in each ofthe two or more frequency channel candidates, from the firstinterference information. Also, the channel deciding unit 139 estimatesthe second interference in each of the two or more frequency channelcandidates again, or causes the interference estimating unit 133 toestimate again.

As described above, for example, the level of the first interference isexpressed by the reception electric power value) of the transmissionsignal (the interference signal) of the transmitter station of theprimary system (the television broadcast system) P_(I,Primary,n)(f).Also, for example, the level of the second interference is expressed bythe electric power value of the interference from communicationinvolving another master WSD 10 of control target (i.e., the receptionelectric power value of the interference signal) P_(I,WSD,n)(f). Then,the channel deciding unit 139 calculates the following worstinterference electric power value P_(I,worst,n)(f), as the interferencelevel including the first interference and the second interference.P _(I,worst,n)(f)=P _(I,Primary,n)(f)+P _(I,WSD,n)(f)  [Math. 5]

Then, for example, the channel deciding unit 139 decides the frequencychannel candidates having minimum worst interference electric powervalue P_(I,worst,n)(f), as the utilizable frequency channel with respectto the k-th master WSD 10.

For example, with this decision of the frequency channel, the utilizablechannel is decided with respect to the master WSD 10, so as to reducethe interference level of the worst time. As a result, the communicationof the master WSD 10 can be improved.

Decision of Frequency Channel with Respect to Master WSD that is notClassified into Group

Also, for example, the channel deciding unit 139 decides the utilizablefrequency channel with respect to the master WSD 10 that is notclassified into any group.

Notification to Master WSD

As described above, the channel deciding unit 139 decides the utilizablefrequency channel with respect to each of the above plurality of masterWSDs 10 of control target. For example, thereafter, the channel decidingunit 139 notifies each master WSD 10 of the decided utilizable frequencychannel via the communication unit 110.

In the above, the method of the decision of the utilizable frequencychannel has been described. Note that, the utilizable frequency channelmay be decided ultimately, so that the interaction for the notificationto the master WSD 10 of the utilizable channel is reduced. For example,it is not such that the utilizable frequency channel is necessarilydecided and notified as described above, but may be such that theutilizable frequency channel is ultimately decided and notified when anadditional predetermined condition is satisfied. As one example, theabove predetermined condition may be a fact that the level of thedifference between the interference in the utilizable channel decidedlast time and the interference in the utilizable frequency channeldecided this time exceeds a predetermined threshold value. That is, whenthe level of the difference does not exceed the predetermined thresholdvalue, the utilizable channel decided the last time may continue to beutilized. Thereby, the interaction for the notification to the masterWSD 10 of the utilizable channel can be reduced. Note that thedetermination of this predetermined condition may be performed for eachmaster WSD, or may be performed for the entire master WSD.

<2.2. Flow of Process>

Next, with reference to FIG. 10, a communication control processaccording to the first embodiment will be described. FIG. 10 is aflowchart illustrating an example of the schematic flow of thecommunication control process according to the first embodiment. Thecommunication control process can be executed for each set 40 of themaster WSDs 10.

First, the interference estimating unit 133 provisionally sets thefrequency channel utilized by each of a plurality of master WSDs 10 ofcontrol target (S301).

Also, the interference estimating unit 133 estimates the firstinterference (the interference from communication involving thecommunication node that is not control target) in each frequency channelcandidate, with respect to each of the above plurality of master WSDs 10(S303).

Also, the interference estimating unit 133 estimates the secondinterference (the interference from communication involving anothercommunication node of control target) in each frequency channelcandidate, with respect to each of the above plurality of master WSDs 10(S305).

Then, the interference information acquiring unit 135 acquires the firstinterference information indicating the above first interference and thesecond interference information indicating the above secondinterference, with respect to each of the above plurality of master WSDs10 (S307).

Thereafter, the classifying unit 137 classifies the above plurality ofmaster WSDs 10 into the first group and the second group, on the basisof the above first interference information and the above secondinterference information with respect to the above plurality of masterWSDs 10 (S309).

Also, the channel deciding unit 139 decides the utilizable frequencychannel with respect to each of one or more master WSDs 10 classifiedinto the above first group (S311).

Thereafter, the channel deciding unit 139 decides the utilizablefrequency channel with respect to each of one or more master WSDs 10classified into the above second group, on the basis of the decisionresult of the frequency channel in the above first group (S313). Here,for example, the channel deciding unit 139 first decides the utilizablefrequency channel with respect to the master WSD 10 having a smallerlevel of the above second interference. Then, the channel deciding unit139 decides the utilizable frequency channel with respect to the masterWSD 10 having a larger level of the above second interference, on thebasis of the decision result of the utilizable frequency channel withrespect to the master WSD 10.

Further, the channel deciding unit 139 notifies each master WSD 10 ofthe decided utilizable frequency channel via the communication unit 110(S315). Then, the process ends.

<2.3. First Exemplary Variant>

Next, with reference to FIG. 11, the first exemplary variant of thefirst embodiment will be described.

(Overview)

As described above, a plurality of groups into which a plurality ofmaster WSDs 10 of control target are classified includes a first groupand a second group. Then, the master WSDs 10 classified into the abovefirst group is the master WSD 10 having a larger level of the abovefirst interference relative to the above second interference, ascompared with the master WSD 10 classified into the above second group.Then, in the example of the first embodiment described above inparticular, the above second group is the group in which the abovefrequency channels are decided after the above first group.

On the other hand, in the exemplary variant of the first embodiment, theabove second group is the group in which the above frequency channelsare decided before the above first group. Then, the exemplary variant ofthe first embodiment also improves communication of a communication nodethat utilizes a radio resource (frequency channel) under an environmentin which there is an interference from communication involving acommunication node that is not control target, with less calculationamount.

(Classifying Unit 137)

The classifying unit 137 classifies the above plurality of master WSDs10 into a plurality of groups related to the decision of the frequencychannel that the master WSD 10 is able to utilize, on the basis of theabove first interference information and the above second interferenceinformation with respect to the above plurality of master WSDs 10 ofcontrol target. This point is as described above in the example of thefirst embodiment.

Also, for example, the above plurality of groups are a plurality ofgroups corresponding to the order in which the above frequency channelsare decided. More specifically, for example, the above plurality ofgroups, at least the above plurality of groups, include at least thefirst group and the second group. These points are also as describedabove in the example of the first embodiment.

Also, for example, the master WSDs 10 classified into the above firstgroup is the master WSD 10 having a larger level of the above firstinterference relative to the above second interference, as compared withthe master WSD 10 classified into the above second group. This point isalso as described above in the example of the first embodiment.

Then, in the first exemplary variant in particular, the above secondgroup is the group in which the above frequency channels are decidedbefore the above first group. As one example, the classifying unit 137classifies the master WSD 10 having a larger level of the above firstinterference relative to the above second interference among the aboveplurality of master WSDs 10, into the first group for which theutilizable frequency channels are decided later. Also, the classifyingunit 137 classifies the master WSD 10 having a smaller level of theabove first interference relative to the above second interference amongthe above plurality of master WSDs 10, into the second group for whichthe utilizable frequency channels are first decided.

By this classification, for example, the utilizable frequency channelswith respect to the master WSD 10 having a comparatively stronginterference in the secondary system relative to the interference fromthe primary system are decided first. Then, the utilizable frequencychannels with respect to the master WSD 10 having a comparatively weakinterference in the secondary system relative to the interference fromthe primary system are decided thereafter.

Hence, after deciding the utilizable frequency channel first withrespect to the master WSD 10 having a comparatively strong interferencein the secondary system relative to the interference from the primarysystem, the utilizable frequency channel can be decided with respect toanother master WSD, so as to reduce the interference to thecommunication of the above master WSD 10. Thereby, a more appropriateutilizable frequency channel with respect to each master WSD 10 can bedecided in the secondary system. As a result, the communication of themaster WSD 10 that secondarily utilizes the frequency channel can beimproved.

Also, the utilizable frequency channel is decided in order for eachgroup (i.e., divided utilizable frequency channels with respect to themaster WSD 10 are decided in order), and therefore the number ofcombinations of the master WSD 10 and the frequency channel candidatedecreases. As a result, the calculation amount can be reduced.

As described above, communication of a communication node that utilizesa radio resource (frequency channel) under an environment in which thereis an interference from communication involving a communication nodethat is not control target is improved with less calculation amount.

(Channel Deciding Unit 139)

Decision in Order According to Group

In particular, in the first exemplary variant, the channel deciding unit139 decides the above frequency channel with respect to each of one ormore master WSDs 10 classified into the above second group. Also, thechannel deciding unit 139 decides the above frequency channel withrespect to each of one or more master WSDs 10 classified into the abovefirst group, on the basis of the decision result of the above frequencychannel in the above second group.

Decision of Frequency Channel in Second Group

In particular, in the first exemplary variant, the channel deciding unit139 decides the above frequency channel with respect to each of one ormore master WSDs 10 classified into the above second group, withoutusing the decision result of the above frequency channel in the abovefirst group. Except this point, it is as described above as the exampleof the first embodiment.

Decision of Frequency Channel in First Group

In particular, in the first exemplary variant, as described above, thechannel deciding unit 139 decides the above frequency channel withrespect to each of one or more master WSDs 10 classified into the abovefirst group, on the basis of the decision result of the above frequencychannel in the above second group.

For example, the channel deciding unit 139 decides one or more frequencychannel candidates, among the two or more frequency channel candidates,as the above frequency channel with respect to the master WSDs 10classified into the above first group. Then, the one or more frequencychannel candidates is one or more frequency channel candidates having asmaller level of the third interference to the above one or more masterWSDs 10 classified into the above second group.

As one example, the above one or more frequency channel candidateshaving a smaller level of the above third interference are the frequencychannel candidates having a smaller maximum level of the level of thethird interference to one or more master WSDs 10 than that of otherfrequency channel candidates.

Note that, as another example, the above one or more frequency channelcandidates having a smaller level of the above third interference may bethe frequency channel candidates having a smaller summation of thelevels of the third interference to one or more master WSDs 10 than thatof other frequency channel candidates.

As described above, the frequency channels in the first group isdecided. Thereby, for example, the interference in the secondary systemcan be made smaller, in the master WSD 10 classified into the secondgroup (for example, the master WSD 10 having a comparatively stronginterference in the secondary system relative to the interference fromthe primary system). Hence, the communication quality of the master WSD10 classified into the second group improves, and the communication ofthe master WSD can be improved.

(Flow of Process)

Next, with reference to FIG. 11, the communication control processaccording to the first exemplary variant of the first embodiment will bedescribed. FIG. 11 is a flowchart illustrating an example of theschematic flow of the communication control process according to thefirst exemplary variant of the first embodiment. The communicationcontrol process can be executed for each set 40 of the master WSDs 10.

Here, steps S401 to S409 and S415 of an example of the communicationcontrol process of the first exemplary variant of the first embodimentdescribed with reference to FIG. 11 are same as steps S301 to S309 andS315 in an example of the communication control process of the firstembodiment described with reference to FIG. 10. Thereby, here, onlysteps S411 and S413 will be described.

Also, the channel deciding unit 139 decides the utilizable frequencychannel with respect to each of one or more master WSDs 10 classifiedinto the above second group (S411). Here, for example, the channeldeciding unit 139 first decides the utilizable frequency channel withrespect to the master WSD 10 having a smaller level of the above secondinterference. Then, the channel deciding unit 139 decides the utilizablefrequency channel with respect to the master WSD 10 having a largerlevel of the above second interference, on the basis of the decisionresult of the utilizable frequency channel with respect to the masterWSD 10.

Thereafter, the channel deciding unit 139 decides the utilizablefrequency channel with respect to each of one or more master WSDs 10classified into the above first group, on the basis of the decisionresult of the frequency channels in the above second group (S313). Here,for example, the channel deciding unit 139 decides one or more frequencychannel candidates having a smaller level of the third interference tothe above one or more master WSDs 10 classified into the above secondgroup, as the utilizable frequency channel with respect to the masterWSDs 10 classified into the above first group.

<2.4. Second Exemplary Variant>

Next, with reference to FIG. 12, the second exemplary variant of thefirst embodiment will be described.

(Overview)

In an example of the above first embodiment, the communication node thatis not control target includes the communication node of the primarysystem. On the other hand, in the second exemplary variant of the firstembodiment, the communication node that is not control target furtherincludes another communication node, in addition to the communicationnode of the primary system.

(Interference Estimating Unit 133)

First Interference from Communication Involving Communication Node thatis not Control Target

First, the interference estimating unit 133 estimates a firstinterference from communication involving the communication node that isnot control target, with respect to each of the above plurality ofmaster WSDs 10.

Communication Node that is not Control Target

For example, the communication node that is not the above control targetincludes a communication node that is not control target by thecommunication control device 100-1.

More specifically, for example, the communication node that is not theabove control target includes a communication node of the primarysystem. That is, as an example of the embodiment of the presentdisclosure, the communication node that is not the above control targetincludes a transmitter station of the television broadcast system.

In particular, in the second exemplary variant of the first embodiment,the communication node that is not the above control target includesanother communication node, in addition to the communication node of theprimary system.

As a first example, the above other communication node is anothercommunication node (for example, the master WSD) of the secondary systemwhich is different from the communication system 1. As one example, theother secondary system is the secondary system which is beyond anycontrol by the communication control device 100-1. Also, as anotherexample, the other secondary system is a secondary system of higherpriority than the communication system 1.

Also, as a second example, when operated in a certain region where thecommunication system 1 exists, the above other communication node is acommunication node of the communication system operated in a regionadjacent to the certain region. As one example, the communication systemoperated in the other region is a primary system or a secondary systemoperated in the other region. In the following, with respect to thispoint, a specific example will be described with reference to FIG. 12.

FIG. 12 is an explanatory diagram for describing an example of thecommunication system operated in another region adjacent to the regionwhere the communication system 1 is operated. Referring to FIG. 12, thecommunication system 1 operated in the region 80A and the communicationsystem 1 operated in the region 80B are illustrated. As one example, theregion 80A and the region 80B each indicate a country, and the borderbetween the region 80A and the region 80B indicates a border betweencountries. Also, as another example, the region 80A and the region 80Beach indicate an area, and the border between the region 80A and theregion 80B indicates a border between the areas. In this example, themaster WSD 10B is not a control target by the communication controldevice 100A. Also, the master WSD 10A is not a control target by thecommunication control device 100B. Thereby, the interference estimatingunit 133 estimates the interference including the interference from theprimary system of the region 80A, the interference from the primarysystem of the region 80B, and the interference from the master WSD 10Bof the region 80B, as the first interference.

Also, as a third example, the above other communication node is a yetanother communication node.

Note that, for example, the interference estimating unit 133 canestimate the above first interference, by separately estimating theinterference from communication involving the communication node of theprimary system and the interference from communication involving theabove other communication node, and summing the calculatedinterferences.

As described above, the communication node that is not the above controltarget includes another communication node, in addition to thecommunication node of the primary system. Then, the first interferenceincluding the interference from communication involving the othercommunication node is estimated. Thereby, not only the communicationnode of the primary system, but also the existence of anothercommunication node that is not control target is considered. Thereby,more appropriate utilizable frequency channel can be decided.

<2.5. Third Exemplary Variant>

Next, the third exemplary variant of the first embodiment will bedescribed.

(Overview)

In the example of the above first embodiment, another communication nodeof control target includes another master WSD 10 of the communicationsystem 1 which is the secondary system. On the other hand, in the thirdexemplary variant of the first embodiment, another communication node ofcontrol target further includes another communication node, in additionto another master WSD 10 of the communication system 1.

(Interference Estimating Unit 133)

Second Interference from Communication Involving Another CommunicationNode of Control Target

Second, the interference estimating unit 133 estimates the secondinterference from communication involving another communication node ofcontrol target, with respect to each of the above plurality of masterWSDs 10 of control target.

Another Communication Node of Control Target

For example, the above other communication node of control target is acommunication node which is control target by the communication controldevice 100-1.

More specifically, for example, the above other communication nodeincludes another master WSDs 10 that are not the master WSD 10 for whichthe interference is estimated, among the above plurality of master WSDs10. As one example, the above other communication node includes anothermaster WSD 10 that is not the master WSD 10 for which the interferenceis estimated and is included in the same set 40 as the master WSD 10 forwhich the interference is estimated, among the above plurality of masterWSDs 10.

In particular, in the third exemplary variant of the first embodiment,the above other communication node of control target includes anothercommunication node, in addition to the above other master WSD 10included in the communication system 1.

Specifically, for example, when the communication control device 100 isinvolved in the decision of the utilizable frequency channel withrespect to the communication node included in another communicationsystem other than the communication system 1, the above othercommunication node includes the above communication node included in theabove other communication system.

As one example, when the communication control device 100 decides theutilizable frequency channel with respect to the master WSD included inanother secondary system other than the communication system 1, theabove other communication node includes the above master WSD included inthe above other secondary system.

Note that, referring to FIG. 11 again, the communication control device100A decides the utilizable frequency channel with respect to the masterWSD 10A, and the communication control device 100B decides theutilizable frequency channel with respect to the master WSD 10B. Then,the communication control device 100A and the communication controldevice 100B cooperate to decide the utilizable frequency channel. Inthis case, the above other communication node for the communicationcontrol device 100A may include the master WSD 10B. Also, the aboveother communication node for the communication control device 100B mayinclude the master WSD 10A.

As described above, the above other communication node of control targetincludes another communication node, in addition to another master WSD10 included in the communication system 1. Then, the second interferenceincluding the interference from communication involving the othercommunication node is estimated. Thereby, not only the master WSD 10included in the communication system 1, but also the existence of anadditional communication node of control target is considered. Thereby,a more appropriate utilizable frequency channel can be decided.

In the above, the first embodiment of the present disclosure has beendescribed. As described above, the first embodiment improvescommunication of a communication node that utilizes a radio resource(frequency channel) under an environment in which there is aninterference from communication involving a communication node that isnot control target, with less calculation amount.

3. SECOND EMBODIMENT

Next, with reference to FIGS. 13 to 16, the second embodiment of thepresent disclosure will be described. According to the second embodimentof the present disclosure, the interference to the communicationinvolving the high priority master WSD from the communication involvingthe low priority master WSD is reduced.

<3.1. Overview>

First, with reference to FIG. 13, the overview of the second embodimentof the present disclosure will be described.

In the second embodiment of the present disclosure, the communicationsystem 1 includes a high priority master WSD of higher priority and alow priority master WSD of lower priority. Then, the low priority masterWSD is controlled so as not to affect the high priority master WSD. Inthe following, with respect to this point, a specific example will bedescribed with reference to FIG. 13.

FIG. 13 is an explanatory diagram for describing an example of themaster WSD included in the communication system 1-2 according to thesecond embodiment. Referring to FIG. 13, the communication system 1-2according to the second embodiment includes a high priority master WSD11 of higher priority and a low priority master WSD 13 of lowerpriority. For example, the high priority master WSD 11 and the lowpriority master WSD 13 are included in the same set 41. Then, thecommunication control device 100-2 decides the utilizable frequencychannel for each low priority master WSD 13, in such a manner that thecommunication of the low priority master WSD 13 does not affect thecommunication of the high priority master WSD 11.

Specifically, in the second embodiment, the utilizable frequency channelwith respect to the high priority master WSD 11 is decided first.Thereafter, the utilizable frequency channel with respect to the lowpriority master WSD 13 is decided on the basis of the decision result ofthe utilizable frequency channel with respect to the high prioritymaster WSD 11.

<3.2. Function and Configuration of Communication Control Device>

With reference to FIG. 14, an example of a configuration of acommunication control device 100-2 according to the second embodimentwill be described. FIG. 14 is a block diagram illustrating an example ofthe configuration of the communication control device 100-2 according tothe second embodiment. Referring to FIG. 14, the communication controldevice 100-2 includes the communication unit 110, the storage unit 120,and a control unit 140.

Here, with respect to the communication unit 110, the storage unit 120,and the set deciding unit 131 of the control unit 140, there is nodifference between the first embodiment and the second embodiment.Thereby, an interference estimating unit 141, an interferenceinformation acquiring unit 143, an interference determination unit 145,a classifying unit 147, and a channel deciding unit 149 of the controlunit 140 will be described.

(Interference Estimating Unit 141)

The interference estimating unit 141 separately calculates theinterference with respect to each of the high priority master WSDs 11 ofhigher priority, and the interference with respect to the low prioritymaster WSD 13 of lower priority.

High Priority Master WSD

The interference estimating unit 141 estimates the interference withrespect to each of a plurality of high priority master WSDs 11 ofcontrol target. For example, the above plurality of high priority masterWSDs 11 are high priority master WSDs 11 included in the same set 41,and the interference estimating unit 141 estimates the aboveinterference for each decided set 41.

First Interference from Communication Involving Communication Node thatis not Control Target

First, the interference estimating unit 141 estimates the firstinterference from communication involving the communication node that isnot control target, with respect to each of the above plurality of highpriority master WSDs 11. The interference estimating unit 141 estimatesthe first interference with respect to each of the high priority masterWSDs 11, in the same way as the interference estimating unit 133according to the first embodiment.

Second Interference from Communication Involving Another CommunicationNode of Control Target

Second, the interference estimating unit 141 estimates the secondinterference from communication involving another communication node ofcontrol target, with respect to each of the above plurality of highpriority master WSDs 11 of control target.

Another Communication Node of Control Target

For example, the above other communication node of control target is acommunication node which is control target by the communication controldevice 100-2.

More specifically, in the second embodiment, for example, the aboveother communication node includes another high priority master WSD 11other than the high priority master WSD 11 for which the interference isestimated, among the above plurality of high priority master WSDs 11. Asone example, the above other communication node includes another highpriority master WSD 11 which is not the high priority master WSD 11 forwhich the interference is estimated but is included in the same set 41as the high priority master WSD 11 for which the interference isestimated, among the above plurality of high priority master WSDs 11.

Also, in the second embodiment, for example, the above othercommunication node does not include the low priority master WSD 13 oflower priority.

Note that the content and the estimation method of the secondinterference are as described in the first embodiment. For example, thesecond interference with respect to the high priority master WSD 11 isexpressed as in the following.P _(I,WSD_High,n)(f)  [Math. 6]

Low Priority Master WSD

The interference estimating unit 141 estimates the interference withrespect to each of a plurality of low priority master WSDs 13 of controltarget. For example, the above plurality of low priority master WSDs 13are low priority master WSDs 13 included in the same set 41, and theinterference estimating unit 141 estimates the above interference foreach decided set 41.

First Interference from Communication Involving Communication Node thatis not Control Target

First, the interference estimating unit 141 estimates the firstinterference from communication involving the communication node that isnot control target, with respect to each of the above plurality of lowpriority master WSDs 13.

Communication Node that is not Control Target

For example, the communication node that is not the above control targetincludes a communication node that is not control target by thecommunication control device 100-1.

More specifically, for example, the communication node that is not theabove control target includes a communication node of the primarysystem. That is, as an example of the embodiment of the presentdisclosure, the communication node that is not the above control targetincludes a transmitter station of the television broadcast system.

Also, in the second embodiment, for example, the communication node thatis not the above control target includes the communication node that isbeyond control at the time of the decision of the utilizable frequencychannel with respect to the low priority master WSD 13, even though itis control target by the communication control device 100-1.

More specifically, for example, the communication node that is not theabove control target further includes the high priority master WSD 11.

Interference

The above first interference is an interference by a downlink signaltransmitted by the communication node that is not the above controltarget or an uplink signal transmitted to the communication node that isnot the above control target. For example, the above first interferenceincludes an interference by a downlink signal transmitted by thetransmitter station of the television broadcast system. Also, the abovefirst interference includes the interference by the downlink signaltransmitted by the high priority WSD 11 or the uplink signal transmittedto the high priority WSD 11.

Also, for example, the above first interference is the interference tothe communication involving the low priority master WSD 13. Morespecifically, the above first interference is the interference to theuplink communication (the transmission to the low priority master WSD 13from the slave WSD 30), and/or the interference to the downlinkcommunication (the transmission to the slave WSD 30 from the lowpriority master WSD 13). In other words, the above first interference isthe interference to the uplink signal received by the low prioritymaster WSD 13 (the transmission signal of the slave WSD 30), and/or theinterference to the downlink signal received by the slave WSD 30 (thetransmission signal of the low priority master WSD 13).

As one example, the above first interference is the interference to theuplink communication (i.e., the interference to the uplink signal).

Estimation of Interference Estimation of Interference of Each FrequencyChannel Candidate

The interference estimating unit 141 estimates the above firstinterference in each of two or more frequency channel candidates, withrespect to each of the above plurality of low priority master WSDs 13.The two or more frequency channel candidates are the frequency channelsthat the communication system 1 is able to utilize secondarily, amongthe frequency channels for the primary system.

Estimation of Electric Power Value

Also, the interference estimating unit 141 estimates a receptionelectric power value of the interference signal for example, as theabove first interference.

For example, the electric power value of the interference fromcommunication involving the communication node of the primary system(i.e., the reception electric power value of the transmission signal(the interference signal) of the transmitter station of the televisionbroadcast system, in the low priority master WSD 13) is expressed as inthe following.P _(I,Primary,n)(f)  [Math. 7]

Also, for example, the electric power value of the interference fromcommunication involving the communication node of the high prioritymaster WSD 11 (i.e., the reception electric power value of thetransmission signal of the high priority master WSD 11 or thetransmission signal (the interference signal) of the slave WSD 30 thatcommunicates with the high priority master WSD 11, in the low prioritymaster WSD 13) is expressed as in the following.P _(I,WSD_High,n)(f)  [Math. 8]

Then, in the second embodiment, for example, the first interference isexpressed as in the following.P _(I,Primary,n)(f)+P _(I,WSD_High,n)(f)  [Math. 9]

Here, n represents an index of the low priority master WSD 13 of targetfor estimating an interference, among the above plurality of lowpriority master WSDs 13. Also, f represents one frequency channelcandidate among a plurality of frequency channel candidates.

Note that the interference estimating unit 141 acquires parameters thatare necessary for referring to the information relevant to the primarysystem, the information relevant to the secondary system, and theinterference electric power, from the DB 50 via the communication unit110, for example. Also, the interference estimating unit 141 acquiresthe information relevant to the already decided utilizable frequencychannel with respect to the high priority master WSD 11. Then, theinterference estimating unit 141 estimates the above first interference,on the basis of the acquired information. As described above, theinformation relevant to the primary system includes the informationrelevant to the communication node (the transmitter station) of theprimary system (e.g., number, position, height of antenna, transmissionelectric power), for example. Also, as described above, the informationrelevant to the secondary system includes, the information relevant tothe master WSD of the secondary system (for example, number, position,height of antenna, transmission electric power), for example.

Second Interference from Communication Involving Another CommunicationNode of Control Target

Second, the interference estimating unit 141 estimates the secondinterference from communication involving another communication node ofcontrol target, with respect to each of the above plurality of lowpriority master WSDs 13 of control target.

Another Communication Node of Control Target

For example, the above other communication node of control target is acommunication node which is control target by the communication controldevice 100-2.

More specifically, in the second embodiment, for example, the aboveother communication node includes another low priority master WSD 13other than the low priority master WSD 13 for which the interference isestimated, among the above plurality of low priority master WSDs 13. Asone example, the above other communication node includes another lowpriority master WSD 13 that is not the low priority master WSD 13 forwhich the interference is estimated but is included in the same set 41as the low priority master WSD 13 for which the interference isestimated, among the above plurality of low priority master WSDs 13.

Also, in the second embodiment, for example, the above othercommunication node does not include the high priority master WSD 11 ofhigher priority.

Note that the content and the estimation method of the secondinterference are as described in the first embodiment. For example, thesecond interference with respect to the low priority master WSD 13 isexpressed as in the following.P _(I,WSD_Low,n)(f)  [Math. 10]

Here, n represents an index of the low priority master WSD 13 of targetfor estimating an interference, among the above plurality of lowpriority master WSDs 13. Also, f represents one frequency channelcandidate among a plurality of frequency channel candidates.

Note that the interference estimating unit 141 acquires the informationrelevant to the secondary system, from the DB 50, via the communicationunit 110, for example. Also, as described above, the interferenceestimating unit 141 suppositionally sets the information relevant to theslave WSD 30 (position, height of antenna, transmission electric power,etc.). Then, the interference estimating unit 141 estimates the abovesecond interference, on the basis of the acquired information and/or thesuppositionally set information. As described above, the informationrelevant to the secondary system includes the information relevant tothe master WSD 10 of the secondary system (for example, number,position, height of antenna, transmission electric power), for example.

(Interference Information Acquiring Unit 143)

High Priority Master WSD

The interference information acquiring unit 143 acquires the firstinterference information indicating the first interference fromcommunication involving the communication node that is not controltarget, with respect to each of a plurality of high priority master WSDs11 of control target.

Also, the interference information acquiring unit 143 acquires thesecond interference information indicating the second interference fromcommunication involving another communication node of control target,with respect to each of a plurality of high priority master WSDs 11 ofcontrol target.

For example, the interference information acquiring unit 143 acquires,as the first interference information, the information indicating thefirst interference estimated by the interference estimating unit 141,with respect to each of a plurality of high priority master WSDs 11 ofcontrol target. Also, the interference information acquiring unit 143acquires, as the second interference information, the informationindicating the second interference estimated by the interferenceestimating unit 141, with respect to each of a plurality of highpriority master WSDs 11 of control target.

Note that the interference information acquiring unit 143 may acquire,as the first interference information, the information indicating thefirst interference that is actually observed, instead of the informationindicating the first interference estimated by the interferenceestimating unit 141.

Low Priority Master WSD

The interference information acquiring unit 143 acquires the firstinterference information indicating the first interference fromcommunication involving the communication node that is not controltarget, with respect to each of a plurality of low and high prioritymaster WSDs 13 of control target.

Also, the interference information acquiring unit 143 acquires thesecond interference information indicating the second interference fromcommunication involving another communication node of control target,with respect to each of a plurality of low and high priority master WSDs13 of control target.

For example, the interference information acquiring unit 143 acquires,as the first interference information, the information indicating thefirst interference estimated by the interference estimating unit 141,with respect to each of a plurality of low and high priority master WSDs13 of control target. Also, the interference information acquiring unit143 acquires, as the second interference information, the informationindicating the second interference estimated by the interferenceestimating unit 141, with respect to each of a plurality of low and highpriority master WSDs 13 of control target.

Note that the interference information acquiring unit 143 may acquire,as the first interference information, the information indicating thefirst interference that is actually observed, instead of the informationindicating the first interference estimated by the interferenceestimating unit 141.

(Interference Determination Unit 145)

The interference determination unit 145 determines whether apredetermined condition (hereinafter, referred to as “interferencecondition”) with respect to the fourth interference to the communicationinvolving the above plurality of high priority master WSDs 11 issatisfied, with respect to each of the above plurality of low prioritymaster WSDs 13.

Estimation of Fourth Interference

For example, the interference determination unit 145 estimates thefourth interference to the communication involving the above pluralityof high priority master WSDs 11, with respect to each of the aboveplurality of low priority master WSDs 13.

Specifically, the utilizable frequency channel with respect to the highpriority master WSD 11 is decided first. Thereby, the interferencedetermination unit 145 estimates the above fourth interference on thebasis of the result of this decision.

Also, for example, the interference determination unit 145 estimates theabove fourth interference for each frequency channel, with respect toeach of the above plurality of low priority master WSDs 13.

Further, for example, the interference determination unit 145 estimatesthe fourth interference of each high priority master WSD 11, for eachfrequency channel candidate.

Also, for example, the interference determination unit 145 estimates thereception electric power value of the interference signal for example,as the above fourth interference. For example, the electric power valueof the interference to the communication involving the high prioritymaster WSD 11 from the communication involving the low priority masterWSD 13 (i.e., the reception electric power value of the downlink signalfrom the low priority master WSD 13 and/or the uplink signal (theinterference signal) to the low priority master WSD 13, in the highpriority master WSD 11) is expressed as in the following.P _(I,Low_To_High,n,i)(f)  [Math. 11]

Here, n represents an index of the low priority master WSD 13. Also, irepresents an index of the high priority master WSD 11. Also, frepresents one of the frequency channel candidates among a plurality offrequency channel candidates.

Determination with Respect to Interference Condition

Then, the interference determination unit 145 determines whether theabove interference condition is satisfied, with respect to each of theabove plurality of low priority master WSDs 13.

For example, the above interference condition is that the level of theabove fourth interference is smaller than a predetermined thresholdvalue. That is, the interference determination unit 145 determineswhether the level of the above fourth interference is smaller than thepredetermined threshold value, with respect to each of the aboveplurality of low priority master WSDs 13.

Also, for example, the interference determination unit 145 determineswhether the level of the above fourth interference is smaller than thepredetermined threshold value, for each frequency channel candidate,with respect to each of the above plurality of low priority master WSDs13.

As a specific process, for example, the interference determination unit145 acquires the maximum one among the levels of the above fourthinterference as in the following, with respect to each of the aboveplurality of low priority master WSDs 13.

$\begin{matrix}{{P_{I,{{Low\_ To}{\_ High}},n,{worst}}(f)} = {\max\limits_{\forall i}{P_{I,{{Low\_ To}{\_ High}},n,i}(f)}}} & \left\lbrack {{Math}.\mspace{14mu} 12} \right\rbrack\end{matrix}$

Then, the interference determination unit 145 performs the followingdetermination, for each frequency channel candidate, with respect toeach of the above plurality of low priority master WSDs 13.P _(I,Low_To_High,n,worst)(f)<P _(I,th)  [Math. 13]

Note that n represents an index of the low priority master WSD 13. Frepresents one of the frequency channel candidates among a plurality offrequency channel candidates. Also, P_(I,th) represents a predeterminedthreshold value.

As described above, the interference determination unit 145 determineswhether the interference condition for the above fourth interference issatisfied for each frequency channel candidate, with respect to each ofthe above plurality of low priority master WSDs 13.

(Classifying Unit 147)

The classifying unit 147 classifies a plurality of high priority masterWSDs 11 and a plurality of low priority master WSDs 13 in a separatedmanner. That is, the classifying unit 147 classifies a plurality of highpriority master WSDs 11 into a plurality of groups. Also, theclassifying unit 147 classifies a plurality of low priority master WSDs13 into a plurality of groups, independently from a plurality of highpriority master WSDs 11. It is to be noted that the high priority masterWSD 11 and the low priority master WSD 13 are not mixed in all groups.

High Priority Master WSD

The classifying unit 147 classifies the above plurality of high prioritymaster WSDs 11 into a plurality of groups related to the decision of thefrequency channel that the high priority master WSD 11 is able toutilize, on the basis of the above first interference information andthe above second interference information with respect to a plurality ofhigh priority master WSDs 11 of control target. Also, for example, theabove plurality of high priority master WSDs 11 are the high prioritymaster WSDs 11 included in the same set 41, and the classifying unit 147classifies the high priority master WSDs 11 for each decided set 41.

Note that the specific method of the classification is as described inthe first embodiment. Specifically, in the second embodiment, forexample, the high priority master WSDs 11 are classified as in thefollowing.

                                      [Math.  14]$n \in \left\{ \begin{matrix}G^{1{st}} & {{{{if}\mspace{14mu}{card}{\left\{ {p❘{{P_{I,{Primary},n}(f)} > {P_{I,{WSD\_ High},n}(f)}}} \right\}/N_{Channel}}} > x},} \\G^{2{nd}} & {else}\end{matrix} \right.$

Here, n represents an index of the high priority master WSD 11 of thetarget to be classified, among the above plurality of high prioritymaster WSDs 11. Also, G^(1st) indicates the first group, and G^(2nd)indicates the second group. Also, f represents one frequency channelcandidate among a plurality of frequency channel candidates. N_(channel)indicates the number of the frequency channel candidates (i.e., thenumber of the frequency channels that the communication system 1 is ableto utilize). P indicates a set of frequency channels that satisfyP_(I,Primary,n)(f)>P_(I,WSD_High,n)(f). Then, card {• • • } is thecardinality of the set. When elements of the set is discrete, card {⋅ ⋅⋅ } is equivalent to the number of the elements of the set (i.e., thenumber of the frequency channel candidates). Also, as described above, xis a threshold value that is larger than 0 and smaller than 1.

Low Priority Master WSD

The classifying unit 147 classifies the above plurality of low prioritymaster WSDs 13 into a plurality of groups related to the decision of thefrequency channel that the low priority master WSD 13 is able toutilize, on the basis of the above first interference information andthe above second interference information with respect to a plurality oflow priority master WSDs 13 of control target. Also, for example, theabove plurality of low priority master WSDs 13 are the low prioritymaster WSDs 13 included in the same set 41, and the classifying unit 147classifies the low priority master WSDs 13 for each decided set 41.

Also, in the second embodiment, for example, the classifying unit 147classifies a plurality of low priority master WSDs 13 on the basis ofthe determination result with respect to the interference condition. Forexample, the classifying unit 147 excludes the low priority master WSD13 that does not satisfy the interference condition with respect to anyfrequency channel candidates from the target of classification, andclassifies the low priority master WSD 13 that satisfies theinterference condition into a plurality of groups.

Note that the specific method of the classification is as described inthe first embodiment. Specifically, in the second embodiment, forexample, the low priority master WSD 13 is classified as in thefollowing.

                                      [Math.  15]$n \in \left\{ \begin{matrix}G^{1{st}} & \begin{matrix}{{if}\mspace{14mu}{card}\left\{ {p❘{{P_{I,{Primary},n}(f)} +}} \right.} \\{{{\left. {{P_{I,{WSD\_ High},n}(f)} > {P_{I,{WSD\_ Low},n}(f)}} \right\}/N_{Channel}} > x},}\end{matrix} \\G^{2{nd}} & {else}\end{matrix} \right.$

Here, n represents an index of the low priority master WSD 13 of thetarget to be classified, among the above plurality of low prioritymaster WSDs 13. Also, G^(1st) indicates the first group, and G^(2nd)indicates the second group. Also, f represents one frequency channelcandidate among a plurality of frequency channel candidates. N_(channel)indicates the number of the frequency channel candidates (i.e., thenumber of the frequency channels that the communication system 1 is ableto utilize). P indicates a set of frequency channels that satisfyP_(I,Primary,n)(f)+P_(I,WSD_High,n)(f)>P_(I,WSD_Low,n)(f). Then, card {•• • } is the cardinality of the set. When elements of the set isdiscrete, card {• • • } is equivalent to the number of the elements ofthe set (i.e., the number of the frequency channel candidates). Also, asdescribed above, x is a threshold value that is larger than 0 andsmaller than 1.

(Channel Deciding Unit 149)

The channel deciding unit 149 decides the utilizable frequency channelwith respect to each of a plurality of master WSDs of control target.

Decision in Order According to Priority

In the second embodiment, the channel deciding unit 149 first decidesthe utilizable frequency channel with respect to each of a plurality ofhigh priority master WSDs 11 of control target. Then, the channeldeciding unit 149 further decides the utilizable frequency channel withrespect to each of the above plurality of low priority master WSDs 13,on the basis of the decision result of the utilizable frequency channelwith respect to the above plurality of high priority master WSDs 11.

With this decision of the frequency channel, for example, the utilizablefrequency channel with respect to the low priority master WSDs 13 can bedecided so as to reduce the interference to the communication of thehigh priority master WSD 11. As a result, the interference to thecommunication involving the high priority master WSD from thecommunication involving the low priority master WSD, from thecommunication involving the low priority master WSD, can be reduced.

High Priority Master WSD

The channel deciding unit 149 decides the utilizable frequency channelwith respect to each of a plurality of high priority master WSDs 11 ofcontrol target.

Note that the specific method of the decision is as described in thefirst embodiment. The channel deciding unit 149 decides the utilizablefrequency channel with respect to each of the high priority master WSDs11, for each group.

Low Priority Master WSD

The channel deciding unit 149 decides the utilizable frequency channelwith respect to each of a plurality of low priority master WSDs 13 ofcontrol target.

Decision of Frequency Channel Based on Determination Result with Respectto Interference Condition

Also, in the second embodiment, for example, the channel deciding unit149 decides the utilizable frequency channel with respect to each of theabove plurality of low priority master WSDs 13, on the basis of thedetermination result with respect to the interference condition.

For example, the channel deciding unit 149 decides that there is noutilizable frequency channel, with respect to the low priority masterWSD 13 that does not satisfy the interference condition in any frequencychannel candidates.

Also, for example, the channel deciding unit 149 decides one of theutilizable frequency channel, with respect to the low priority masterWSD 13 that satisfies the interference condition in one of the frequencychannel candidates. Specifically, for example, with respect to such alow priority master WSD 13, the channel deciding unit 149 decides one ofthe frequency channel candidates in which the interference condition issatisfied, as the utilizable frequency channel.

As one example, the channel deciding unit 149 decides the utilizablefrequency channel with respect to each of the low priority master WSD13, for each group, in the same way as the method of the decisiondescribed in the first embodiment. Note that, as described above,instead of all frequency channel candidates, one of the frequencychannel candidates is decided as the utilizable frequency channel fromamong the frequency channel candidates in which the interferencecondition is satisfied.

Also, as another example, the channel deciding unit 149 may decide thefrequency channel candidate in which the interference condition issatisfied, as the utilizable frequency channel, not for each group, butwith respect to each low priority master WSD 13.

As described above, the interference to the communication involving thehigh priority master WSD from the communication involving the lowpriority master WSD, from the communication involving the low prioritymaster WSD, can be reduced by the decision based on the determinationresult with respect to the interference condition.

As described above, the channel deciding unit 149 decides the utilizablefrequency channel with respect to each master WSD of control target. Forexample, thereafter, the channel deciding unit 149 notifies each masterWSD of the decided utilizable frequency channel, via the communicationunit 110.

In the above, the function and configuration of the communicationcontrol device 100-2 according to the second embodiment has beendescribed. Note that the hardware configuration of the communicationcontrol device 100-2 according to the second embodiment is same as thehardware configuration of the communication control device 100-1according to the first embodiment.

<3.3. Flow of Process>

Next, with reference to FIGS. 15 and 16, the communication controlprocess according to the second embodiment will be described.

(Overall Flow)

FIG. 15 is a flowchart illustrating an example of the schematic flow ofthe communication control process according to the second embodiment.The communication control process can be executed for each set 41 of themaster WSDs.

First, the control unit 140 executes the frequency channel decidingprocess with respect to the high priority master WSD 11 (S500).

Thereafter, the control unit 150 executes the frequency channel decidingprocess with respect to the low priority master WSD 13 (S600).

Note that the frequency channel deciding process (S500) with respect tothe high priority master WSD 11 is same as the communication controlprocess (S300) of the first embodiment described with reference to FIG.10.

(Overall Flow)

FIG. 16 is a flowchart illustrating an example of the schematic flow ofthe frequency channel deciding process (S600) with respect to the lowpriority master WSD 13.

First, the interference determination unit 145 estimates the fourthinterference (the interference to the communication involving the highpriority master WSD 11) of each high priority master WSD 11, for eachfrequency channel, with respect to each of a plurality of low prioritymaster WSDs 13 of control target (S601).

Thereafter, the interference determination unit 145, the interferencedetermination unit 145 determines whether the interference condition issatisfied, with respect to each of the above plurality of low prioritymaster WSDs 13 (S603).

The interference estimating unit 141 provisionally sets the frequencychannel utilized by each of the low priority master WSDs 13 (S605).

Also, the interference estimating unit 141 estimates the firstinterference (the interference from the communication involving thecommunication node of the primary system and the communication involvingthe high priority master WSD 11) in each frequency channel candidate,with respect to each of the above plurality of low priority master WSDs13 (S607).

Also, the interference estimating unit 141 estimates the secondinterference (the interference from communication involving another lowpriority master WSD 13) in each frequency channel candidate, withrespect to each of the above plurality of low priority master WSDs 13(S609).

Then, the interference information acquiring unit 143 acquires the firstinterference information indicating the above first interference and thesecond interference information indicating the above secondinterference, with respect to each of the above plurality of lowpriority master WSDs 13 (S611).

Thereafter, the classifying unit 147 classifies the above plurality oflow priority master WSDs 13 into the first group and the second group,on the basis of the above first interference information and the abovesecond interference information with respect to the above plurality oflow priority master WSDs 13 (S613).

Also, the channel deciding unit 149 decides the utilizable frequencychannel with respect to each of one or more low priority master WSDs 13classified into the above first group (S615).

Thereafter, the channel deciding unit 149 decides the utilizablefrequency channel with respect to each of one or more low prioritymaster WSDs 13 classified into the above second group, on the basis ofthe decision result of the frequency channel with respect to the highpriority master WSD 11 and the decision result of the frequency channelin the above first group (S617).

Further, the channel deciding unit 149 notifies each master WSD of thedecided utilizable frequency channel via the communication unit 110(S619). Then, the process ends.

In the above, the second embodiment of the present disclosure has beendescribed. Note that the same transformation as each exemplary variant(the first exemplary variant, the second exemplary variant, and thethird exemplary variant) of the first embodiment may be applied to thesecond embodiment.

4. APPLICATION EXAMPLE

Next, with reference to FIG. 17, an application example of theembodiment of the present disclosure will be described.

In the example of the above embodiment, the communication system 1 isthe secondary system that secondarily utilizes the frequency channel(TVWS) of the primary system. Then, the communication node that is notcontrol target includes the communication node (the transmitter station)of the primary system (the television broadcast system). Also, each of aplurality of communication nodes of control target is the communicationnode (the master WSD) of the secondary system that secondarily utilizesthe frequency channel for the above primary system.

However, the embodiment of the present disclosure is not limited to suchan example. For example, as an application example of the embodiment ofthe present disclosure, the communication system 1 is a communicationsystem relevant to mobile communication. Also, the communication nodethat is not control target includes a base station of macro cell. Also,each of a plurality of communication nodes of control target is a basestation of small cell that partially or entirely overlaps the abovemacro cell. In the following, with respect to this point, a specificexample will be described with reference to FIG. 17.

FIG. 17 is an explanatory diagram for describing an application exampleof the embodiment of the present disclosure. Referring to FIG. 17, abase station 67 of a macro cell 69, base stations 15 of a small cells21, and terminal devices 31 that are able to communicate with the basestations are illustrated. Also, the DB 51 and the communication controldevice 101 are illustrated.

In this example, the base station 15 of the small cell 21 communicateswirelessly by utilizing the frequency channel for the base station 67 ofthe macro cell 69.

Also, the DB 51 collects and retains various information. For example,the DB 51 collects and retains various types of information for decidingthe utilizable frequency channel with respect to the base station 15 ofeach small cell 21. Specifically, for example, the DB 51 collects theinformation relevant to the base station 67 of the macro cell 69. Also,for example, the DB 51 collects the information relevant to the basestation 15 of the small cell 21. Also, for example, the DB 50 acquiresthe parameters necessary for referring to the interference electricpower.

The communication control device 101 executes various processes relevantto the control of the base station 15 of the small cell 21. For example,the processes includes a process relevant to decision of the utilizablefrequency channel with respect to each base station 15. Note that thecommunication control device 101 can operate in the same way as thecommunication control device 100 of the above each embodiment. Also, thecommunication control device 101 can include the same components (forexample, the interference information acquiring unit, the classifyingunit, the channel deciding unit, and the interference determinationunit, and others) as the communication control device 100 of the aboveeach embodiment.

5. SPECIFIC EXAMPLE OF COMMUNICATION CONTROL DEVICE

The technology according to the present disclosure can be applied tovarious products. For example, the communication control device 100 (andthe communication control device 101) may be configured as a server of atype such as a tower server, a rack server, or a blade server. Also,components of at least a part of the communication control device 100(and the communication control device 101) may be configured as a modulemounted on a server (for example, an integrated circuit moduleconfigured by one die, or a card or blade inserted into a slot of ablade server).

FIG. 18 is a block diagram illustrating an example of the schematicconfiguration of a server 700 to which the technology according to thepresent disclosure can be applied. The server 700 includes a processor701, a memory 702, a storage 703, a network interface 704, and a bus706.

The processor 701 is a central processing unit (CPU) or a digital signalprocessor (DSP) for example, and controls various types of functions ofthe server 700. The memory 702 includes a random access memory (RAM) anda read only memory (ROM), and stores programs and data executed by theprocessor 701. The storage 703 can include a storage medium, such as asemiconductor memory or a hard disk.

The network interface 704 is a wired communication interface forconnecting the server 700 to a wired communication network 705. Thewired communication network 705 may be a core network such as an evolvedpacket core (EPC), or may be a packet data network (PDN) such as theInternet.

The bus 706 connects the processor 701, the memory 702, the storage 703,and the network interface 704 to each other. The bus 706 may include twoor more buses of different speeds (for example, a high-speed bus and alow-speed bus).

In the server 700 illustrated in FIG. 18, the interference informationacquiring unit 135, the classifying unit 137, and/or the channeldeciding unit 139 described with reference to FIG. 7 may be implementedon the processor 701. As one example, a program for causing a processorto function as the interference information acquiring unit 135, theclassifying unit 137, and/or the channel deciding unit 139 (in otherwords, a program for causing a processor to execute the operation of theinterference information acquiring unit 135, the classifying unit 137,and/or the channel deciding unit 139) may be installed in the server700, in order for the processor 701 to execute the program. As anotherexample, the server 700 is equipped with a module including theprocessor 701 and the memory 702 (for example, an information processingapparatus), and the interference information acquiring unit 135, theclassifying unit 137, and/or the channel deciding unit 139 may beimplemented in the module. In this case, the above module may store aprogram for causing a processor to function as the interferenceinformation acquiring unit 135, the classifying unit 137, and/or thechannel deciding unit 139 in the memory 702, in order for the processor701 to execute the program. As described above, the server 700 or theabove module may be provided as the device including the interferenceinformation acquiring unit 135, the classifying unit 137, and/or thechannel deciding unit 139, or alternatively the above program forcausing a processor to function as the interference informationacquiring unit 135, the classifying unit 137, and/or the channeldeciding unit 139 may be provided. Also, a readable storage medium thatcan store the above program may be provided. With respect to thesepoints, the interference information acquiring unit 143, theinterference determination unit 145, the classifying unit 147, and/orthe channel deciding unit 149 described with reference to FIG. 14 arealso same as the interference information acquiring unit 135, theclassifying unit 137, and/or the channel deciding unit 139.

6. CONCLUSION

The communication control device and each process according to theembodiments of the present disclosure have been described so far, usingFIGS. 1 to 18. According to the embodiments according to the presentdisclosure, the first interference information indicating the firstinterference from communication involving the communication node that isnot control target is acquired with respect to each of a plurality ofcommunication nodes of control target. Also, the second interferenceinformation indicating the second interference from communicationinvolving another communication node of control target is acquired, withrespect to each of a plurality of communication nodes of control target.Then, the above plurality of the communication nodes are classified intoa plurality of groups related to the decision of the frequency channelthat the communication node is able to utilize, on the basis of theabove first interference information and the above second interferenceinformation.

Thereby, communication of a communication node that utilizes a radioresource (frequency channel) under an environment in which there is aninterference from communication involving a communication node that isnot control target is improved with less calculation amount.

Also, for example, the above plurality of groups are a plurality ofgroups corresponding to the order in which the above frequency channelsare decided. More specifically, for example, the above plurality ofgroups include at least the first group and the second group. Above

Also, for example, the communication node classified into the abovefirst group is the communication node having a larger level of the abovefirst interference relative to the above second interference, ascompared with the communication node classified into the above secondgroup.

Also, for example, the above second group is the group in which theabove frequency channels are decided after the above first group.

By this classification, for example, the utilizable frequency channelswith respect to the master WSD 10 having a comparatively weakinterference in the secondary system relative to the interference fromthe primary system are decided first. Then, the utilizable frequencychannels with respect to the master WSD 10 having a comparatively stronginterference in the secondary system relative to the interference fromthe primary system are decided thereafter. That is, the utilizablefrequency channels with respect to the master WSD 10 having a smallerinfluence on the interference by the decision of the utilizablefrequency channels in the secondary system (for example, the fluctuationof the interference level) are decided first. Then, the utilizablefrequency channels with respect to the master WSD 10 having a largerinfluence on the interference by the decision of the utilizablefrequency channel in the secondary system (for example, the fluctuationof the interference level) are decided thereafter.

Hence, a more appropriate utilizable frequency channel is decided withrespect to the master WSD 10 having a larger influence of the decisionof the utilizable frequency channel in the secondary system, inconsideration of the utilizable frequency channels that are alreadydecided with respect to other master WSDs 10. On the other hand, withrespect to the master WSD 10 having a smaller influence of the decisionof the utilizable frequency channel in the secondary system, theinfluence (for example, the fluctuation of the interference level)occurs by the following decision of the utilizable frequency channelwith respect to other master WSDs 10, but the influence is small.Thereby, a more appropriate utilizable frequency channel with respect toeach master WSD 10 can be decided in the secondary system. As a result,the communication of the master WSD 10 that secondarily utilizes thefrequency channel can be improved.

Also, the utilizable frequency channel is decided in order for eachgroup (i.e., divided utilizable frequency channels with respect to themaster WSD 10 are decided in order), and therefore the number ofcombinations of the master WSD 10 and the frequency channel candidatedecreases. As a result, the calculation amount can be reduced.

Further, for example, of the two or more frequency channel candidates,one or more frequency channel candidates having a smaller level of theabove first interference are decided as the utilizable frequency channelwith respect to the master WSDs 10 classified into the above firstgroup.

This decision of the frequency channel reduces the interference from theprimary system in the master WSD 10 classified into the first group (forexample, the master WSD 10 having a comparatively strong interferencefrom the primary system relative to the interference in the secondarysystem), for example. Hence, the communication quality of the master WSD10 classified into the first group improves, and the communication ofthe master WSD can be improved. Note that this decision is effective, inparticular when there is a variation in the level of the interferencefrom the primary system by the frequency channel candidate.

Also, the above second group may be the group in which the abovefrequency channels are decided before the above first group.

By this classification, for example, the utilizable frequency channelswith respect to the master WSD 10 having a comparatively stronginterference in the secondary system relative to the interference fromthe primary system are decided first. Then, the utilizable frequencychannels with respect to the master WSD 10 having a comparatively weakinterference in the secondary system relative to the interference fromthe primary system are decided thereafter.

Hence, after deciding the utilizable frequency channel first withrespect to the master WSD 10 having a comparatively strong interferencein the secondary system relative to the interference from the primarysystem, the utilizable frequency channel can be decided with respect toanother master WSD, so as to reduce the interference to thecommunication of the above master WSD 10. Thereby, a more appropriateutilizable frequency channel with respect to each master WSD 10 can bedecided in the secondary system. As a result, the communication of themaster WSD 10 that secondarily utilizes the frequency channel can beimproved.

Also, the utilizable frequency channel is decided in order for eachgroup (i.e., divided utilizable frequency channels with respect to themaster WSD 10 are decided in order), and therefore the number ofcombinations of the master WSD 10 and the frequency channel candidatedecreases. As a result, the calculation amount can be reduced.

Further, one or more frequency channel candidates having a smaller levelof the third interference to the above one or more master WSDs 10classified into the above second group may be decided as the abovefrequency channels with respect to the master WSDs 10 classified intothe above first group.

Thereby, for example, the interference in the secondary system can bemade smaller, in the master WSD 10 classified into the second group (forexample, the master WSD 10 having a comparatively strong interference inthe secondary system relative to the interference from the primarysystem). Hence, the communication quality of the master WSD 10classified into the second group improves, and the communication of themaster WSD can be improved.

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples, of course. Aperson skilled in the art may find various alterations and modificationswithin the scope of the appended claims, and it should be understoodthat they will naturally come under the technical scope of the presentdisclosure.

For example, although an example in which the secondarily utilized radioresource is the frequency channel has been described, the presentdisclosure is not limited to such an example. The radio resource may beradio resources other than the frequency channel. For example, the aboveradio resource may be spreading codes, when code division multipleaccess (CDMA), wideband code division multiple access (WCDMA)(registered trademark), or a similar method is employed.

Also, although an example in which the communication node (the masterWSD) is classified into two groups has been described, the presentdisclosure is not limited to such an example. For example, thecommunication node (the master WSD) may be classified into three or moregroups. For example, the utilizable frequency channel may be decided inorder in each group.

Also, although an example in which a high priority communication node (ahigh priority master WSD) and a low priority communication node (a lowpriority master WSD) exist has been described, the present disclosure isnot limited to such an example. For example, a high prioritycommunication node (a high priority master WSD), an intermediatepriority communication node (an intermediate priority master WSD), and alow priority communication node (a low priority master WSD) may exist.Also, further various types of priorities may be provided. In this case,for example, the utilizable frequency channel may be decided in orderfrom the communication node having a higher priority. Then, theutilizable frequency channel with respect to the communication nodehaving a lower priority may be decided on the basis of the decisionresult of the utilizable frequency channel with respect to thecommunication node having a higher priority.

Also, although an example in which the communication control device usesa specific decision method of the utilizable frequency channel has beendescribed, the present disclosure is not limited to such an example. Forexample, the communication control device may selectively combine anduse the above specific decision method and other methods. As oneexample, when the number of combinations of the communication node (themaster WSD) and the frequency channel candidate is large, the abovespecific decision method may be used, and when the number ofcombinations is small, another method may be used. The other method maybe full search, greedy algorithm, local search, genetic algorithm, orthe like, for example. Also, the full search, the greedy algorithm, thelocal search, the genetic algorithm, or the like may be used for eachgroup.

Also, although an example in which the primary system is the televisionbroadcast system, and the secondary system is the communication systemthat secondarily utilizes the TVWS has been described, the presentdisclosure is not limited to such an example. The primary system and thesecondary system may be the primary system and the secondary system ofother types.

Also, although an example in which the communication control device isan independent device has been described, the present disclosure is notlimited to such an example. The communication control device may beimplemented in another device. As one example, the communication controldevice may be implemented in the DB. Also, as another example, thecommunication control device may be implemented in the regulatory DB. Inthis case, the regulatory DB may also collect various types ofinformation from the master WSD, the DB, and others. Also, as yetanother example, the communication control device may be implemented inthe master WSD. In this case, as one example, the master WSD may executethe classification of a plurality of master WSDs to a plurality ofgroups, the decision of the utilizable radio resource (the frequencychannel), or other processing, as a representative. Also, as anotherexample, the master WSD may control a plurality of communication nodesthat are dependent on the master WSD and execute the classification ofthe plurality of communication nodes to the groups, the decision of theutilizable radio resource (the frequency channel), or other processing.

Also, although an example in which one communication control device andone DB control one region has been described, the present disclosure isnot limited to such an example. For example, one communication controldevice and/or one DB may control a plurality of regions. Also, aplurality of communication control devices and/or a plurality of DBs maycontrol one region.

Also, the process steps in the communication control process of thepresent specification are needless to be executed in temporal sequencealong the order described in the flowchart. For example, the processsteps in the communication control process may be executed in adifferent order from the order described in the flowchart, or may beexecuted in parallel.

Also, a computer program for causing the processor equipped in thecommunication control device of the present specification (for example,CPU, DSP, or the like) to function as the components of the abovecommunication control device (for example, the interference informationacquiring unit, the classifying unit, the channel deciding unit, and/orthe interference determination unit) (in other words, a computer programfor causing the above processor to execute the operation of thecomponents of the above communication control device) can be created.Also, a storage medium that stores the computer program may be provided.Also, an information processing apparatus (for example, a completedproduct or a module (a component, a processing circuit, or a chip, forexample) for the completed product) including a memory that stores theabove computer program and one or more processors capable of executingthe above computer program may be provided. Also, a method including theoperation of the components (for example, the interference informationacquiring unit, the classifying unit, the channel deciding unit, and/orthe interference determination unit, for example) of the abovecommunication control device is included in the technology according tothe present disclosure.

Additionally, the present technology may also be configured as below.

(1)

A communication control device including:

an acquisition unit configured to acquire first interference informationindicating a first interference from communication involving acommunication node that is not control target and second interferenceinformation indicating a second interference from communicationinvolving another communication node of control target, with respect toeach of a plurality of communication nodes of control target; and

a classifying unit configured to classify the plurality of communicationnodes into a plurality of groups related to a decision of a radioresource that a communication node is able to utilize, on the basis ofthe first interference information and the second interferenceinformation with respect to the plurality of communication nodes.

(2)

The communication control device according to (1), wherein

the plurality of groups are a plurality of groups corresponding to anorder in which the radio resource is decided.

(3)

The communication control device according to (2), wherein

the plurality of groups include at least a first group and a secondgroup, and

a communication node classified into the first group is a communicationnode in which a level of the first interference relative to the secondinterference is larger, as compared with a communication node classifiedinto the second group.

(4)

The communication control device according to (3), wherein

the second group is a group for which the radio resource is decidedafter the first group.

(5)

The communication control device according to (4), further including:

a deciding unit configured to decide the radio resource with respect toeach of the plurality of communication nodes,

wherein the deciding unit decides the radio resource with respect toeach of one or more communication nodes classified into the first group,and decides the radio resource with respect to each of one or morecommunication nodes classified into the second group, on the basis of adecision result of the radio resource in the first group.

(6)

The communication control device according to (5), wherein

the deciding unit decides one or more radio resource candidates having asmaller level of the first interference among two or more radio resourcecandidates, as the radio resource for the communication node classifiedinto the first group.

(7)

The communication control device according to (3), wherein

the second group is a group for which the radio resource is decidedbefore the first group.

(8)

The communication control device according to (7), further including:

a deciding unit configured to decide the radio resource with respect toeach of the plurality of communication nodes,

wherein the deciding unit decides the radio resource with respect toeach of one or more communication nodes classified into the secondgroup, and decides the radio resource with respect to each of one ormore communication nodes classified into the first group, on the basisof a decision result of the radio resource in the second group.

(9)

The communication control device according to (8), wherein

the deciding unit decides one or more radio resource candidates having asmaller level of a third interference with the one or more communicationnodes classified into the second group among two or more radio resourcecandidates, as the radio resource for the communication node classifiedinto the first group.

(10)

The communication control device according to any one of (3) to (9),further including:

a deciding unit configured to decide the radio resource with respect toeach of the plurality of communication nodes,

wherein, when deciding the radio resource with respect to each of theone or more communication nodes classified into the second group, thedeciding unit decides the radio resource with respect to thecommunication node having a smaller level of the second interference,and decides, on the basis of a decision result of the radio resourcewith respect to the communication node, the radio resource with respectto the communication node having a larger level of the secondinterference.

(11)

The communication control device according to any one of (3) to (10),further including:

a deciding unit configured to decide the radio resource with respect toeach of the plurality of communication nodes,

wherein the deciding unit decides one or more radio resource candidateshaving a smaller level of interference including the first interferenceand the second interference among two or more radio resource candidates,as the radio resource for the communication node classified into thesecond group.

(12)

The communication control device according to any one of (3) to (11),wherein

the first interference information indicates the first interference ineach of two or more radio resource candidates,

the second interference information indicates the second interference ineach of the two or more radio resource candidates, and

the level of the first interference relative to the second interferencecorresponds to the number of the radio resource candidates for which alevel of the first interference is larger than a level of the secondinterference by a predetermined threshold value or more.

(13)

The communication control device according to any one of (1) to (13),further including:

a deciding unit configured to decide the radio resource with respect toeach of the plurality of communication nodes,

wherein the plurality of communication nodes are communication nodes ofa higher priority than one or more low priority communication nodes ofcontrol target, and

the deciding unit further decides the radio resource with respect toeach of the one or more low priority communication nodes, on the basisof a decision result of the radio resource with respect to the pluralityof communication nodes.

(14)

The communication control device according to (13), further including:

a determination unit configured to determine whether a predeterminedcondition for a fourth interference with communication involving theplurality of communication nodes is satisfied, with respect to each ofthe one or more low priority communication nodes,

wherein the deciding unit decides the radio resource with respect toeach of the one or more low priority communication nodes, on the basisof a determination result with respect to the predetermined condition.

(15)

The communication control device according to any one of (1) to (14),wherein

the first interference is an interference by a downlink signaltransmitted by the communication node that is not control target or anuplink signal transmitted to the communication node that is not controltarget, and

the second interference is an interference by a downlink signaltransmitted by the other communication node or an uplink signaltransmitted to the other communication node.

(16)

The communication control device according to (15), wherein

the interference by the uplink signal transmitted to the othercommunication node is an interference estimated under an assumption thata transmission node that transmits the uplink signal to the othercommunication node exists in a predetermined range or at a predeterminedposition which are closer to the communication node of control targetwithin a communication range of the other communication node.

(17)

The communication control device according to any one of (1) to (16),wherein

the communication node that is not control target includes acommunication node of a primary system, and

each of the plurality of communication nodes is a communication node ofa secondary system that secondarily utilizes a radio resource for theprimary system.

(18)

The communication control device according to any one of (1) to (16),wherein

the communication node that is not control target includes a basestation of a macro cell, and

each of the plurality of communication nodes is a base station of asmall cell that overlaps the macro cell partially or entirely.

(19)

A communication control method including:

acquiring first interference information indicating a first interferencefrom communication involving a communication node that is not controltarget and second interference information indicating a secondinterference from communication involving another communication node ofcontrol target, with respect to each of a plurality of communicationnodes of control target; and

classifying the plurality of communication nodes into a plurality ofgroups related to a decision of a radio resource that a communicationnode is able to utilize, on the basis of the first interferenceinformation and the second interference information with respect to theplurality of communication nodes.

(20)

An information processing apparatus including:

a memory that stores a predetermined program; and

a processor configured to execute the predetermined program,

wherein the predetermined program is a program for executing

acquiring first interference information indicating a first interferencefrom communication involving a communication node that is not controltarget and second interference information indicating a secondinterference from communication involving another communication node ofcontrol target, with respect to each of a plurality of communicationnodes of control target, and

classifying the plurality of communication nodes into a plurality ofgroups related to a decision of a radio resource that a communicationnode is able to utilize, on the basis of the first interferenceinformation and the second interference information with respect to theplurality of communication nodes.

REFERENCE SIGNS LIST

-   1 communication system-   10 master white space device (WSD)-   11 high priority master WSD-   13 low priority master WSD-   15 base station (of small cell)-   20 communication range-   21 small cell-   30 slave WSD-   31 terminal device-   50, 51 data base (DB)-   60 transmitter station-   67 base station (of macro cell)-   69 macro cell-   100, 101 communication control device-   135, 143 interference information acquiring unit-   137, 147 classifying unit-   139, 149 channel deciding unit-   145 interference determination unit

The invention claimed is:
 1. A communication control device, comprising:a memory; and processing circuitry configured to acquire interferenceinformation indicating an interference, from a communication node thatis not a control target, with respect to each communication node of aplurality of communication nodes that are control targets; classify theplurality of communication nodes into a plurality of groups based on theinterference information, wherein the plurality of groups includes atleast a first group and a second group, and the communication node thatis not the control target has a higher degree of interference from anycommunication node classified into the first group than form anycommunication node classified into the second group; decide a firstallocation result, the first allocation result indicating a radioresource allocable to each of one or more communication nodes classifiedinto either group of the first group or the second group; and decide asecond allocation result based on the first allocation result, thesecond allocation result indicating the radio resource allocable to eachof one or more communication nodes classified into another group of thefirst group or the second group, the another group being different thanthe one group.
 2. The communication control device according to claim 1,wherein the plurality of groups correspond to an order in which theradio resource is decided.
 3. The communication control device accordingto claim 1, wherein the second group is decided after the first group.4. The communication control device according to claim 1, wherein theprocessing circuitry decides one or more radio resource candidates,having a smaller level of interference among two or more radio resourcecandidates, as the radio resource for a communication node classifiedinto the first group.
 5. The communication control device according toclaim 1, wherein the second group is decided before the first group. 6.The communication control device according to claim 1, wherein theinterference information indicates the interference in each of two ormore radio resource candidates, and a degree of the interferencecorresponds to a number of radio resource candidates for which a levelof the interference is larger than a predetermined threshold value. 7.The communication control device according to claim 1, wherein theplurality of communication nodes are communication nodes with a higherpriority than one or more low priority communication nodes that arecontrol targets, and the processing circuitry further decides the radioresource allocable to each of one or more low priority communicationnodes based on a decision result of the radio resource with respect tothe plurality of communication nodes.
 8. The communication controldevice according to claim 7, wherein the processing circuitry is furtherconfigured to determine whether a predetermined condition, for anotherinterference with communication involving the plurality of communicationnodes, is satisfied with respect to each of the one or more low prioritycommunication nodes, and the processing circuitry decides the radioresource allocable to each of one or more low priority communicationnodes, based on a determination result with respect to the predeterminedcondition.
 9. The communication control device according to claim 1,wherein the interference is by a downlink signal transmitted by thecommunication node that is not a control target or an uplink signaltransmitted to the communication node that is not a control target. 10.The communication control device according to claim 1, wherein thecommunication node that is not the control target is a communicationnode of a primary system.
 11. The communication control device accordingto claim 1, wherein the communication node that is not the controltarget includes a first base station of a macro cell, and each of theplurality of communication nodes is a base station of a small cell thatoverlaps the macro cell.
 12. The communication control device accordingto claim 1, wherein the communication node that is not the controltarget includes a communication node controlled by another communicationcontrol device.
 13. The communication control device according to claim1, wherein the plurality of communication nodes is part of a secondarysystem that uses a part or whole of a spectrum assigned to a primarysystem, and the processing circuitry is configured to controlcommunication by the plurality of communication nodes.
 14. Thecommunication control device according to claim 1, wherein the pluralityof communication nodes are white space devices.
 15. A communicationcontrol method, comprising: acquiring interference informationindicating an interference, by processing circuitry of a communicationcontrol device and from a communication node that is not a controltarget, with respect to each communication node of a plurality ofcommunication nodes that are control targets; classifying, by theprocessing circuitry, the plurality of communication nodes into aplurality of groups based on the interference information, wherein theplurality of groups includes at least a first group and a second group,and the communication node that is not the control target has a higherdegree of interference from any communication node classified into thefirst group than form any communication node classified into the secondgroup; deciding a first allocation result, the first allocation resultindicating a radio resource allocable to each of one or morecommunication nodes classified into either group of the first group orthe second group; and deciding a second allocation result based on thefirst allocation result, the second allocation result indicating theradio resource allocable to each of one or more communication nodesclassified into another group of the first group or the second group,the another group being different than the one group.
 16. Thecommunication control method according to claim 15, wherein theplurality of groups correspond to an order in which the radio resourceis decided.
 17. The communication control method according to claim 15,wherein the second group is decided after the first group.
 18. Anon-transitory computer readable medium storing computer executableinstructions which, when executed by processing circuitry of aninformation processing device, causes the information processing deviceto: acquiring interference information indicating an interference, froma communication node that is not a control target, with respect to eachcommunication node of a plurality of communication nodes that arecontrol targets; classifying the plurality of communication nodes into aplurality of groups based on the interference information, wherein theplurality of groups includes at least a first group and a second group,and the communication node that is not the control target has a higherdegree of interference from any communication node classified into thefirst group than form any communication node classified into the secondgroup; deciding a first allocation result, the first allocation resultindicating a radio resource allocable to each of one or morecommunication nodes classified into either group of the first group orthe second group; and deciding a second allocation result based on thefirst allocation result, the second allocation result indicating theradio resource allocable to each of one or more communication nodesclassified into another group of the first group or the second group,the another group being different than the one group.
 19. Thenon-transitory computer readable medium according to claim 18, whereinthe plurality of groups corresponds to an order in which the radioresource is decided.
 20. The non-transitory computer readable mediumaccording to claim 18, wherein the second group is decided after thefirst group.